Infrared spectra
Introduction
The infrared spectra of organic compounds are associated with transitions between vibrational energy level. Molecular vibrations may be detected and measured either in an infrared spectrum or indirectly in a Raman spectrum. The most useful vibrations, from the point of view of the organic chemist , occur in the narrower range of 2.5-16μm. The position of an absorption band in the spectrum may be expressed in microns, but standard practice uses a frequency scale in the form of wavenumbers, which are the reciprocals of the wavelength,cm-1.The useful range of the infrared for an organic chemist is between 4000 cm-1 at the high-frequency end and 625 cm-1 at the low frequency end.
Many function groups have vibration frequencies,characteristic of that functional group,within well-defined regions of the range;these are summarised in Charts 1-4 at the end of this chapter, with more detail in the tables of data that follow.because many functional groups can be identified by their characteristic vibration frequencies,the infrared spectrum is the simplest, most rapid, and often most most reliable means for identifying the functional groups.
Equation 2.1,which is derived from the model of a mass m
vibrating at frequency v on the end of a fixed spring, is useful in understanding the range of values of the vibrational frequencies of various kinds of bonds.
Where k is a measure of the strength of spring.However,in chemical bonds, one end of the “spring”(bond) is not fixed, but rather there are two mass(m1 and m2)involved and each is able to move.the m of Eq.2.1 is mow determined by the relationship in Eq.2.2
If one of the masses (say,m1) is infinitely large 1/m1 is then zero,and the relevant mass m for Eq.2.1 is simply that of m2 --making it analogous to the case where one end of the “spring”is fixed.
Simple substitutions of masses in these equations allow us to understand that with other things being equal:(1)C-H bonds will have higher stretching frequencies than C-C bonds , which in turn are likely to be higher than C-halogen bonds;(2)O-H bonds will have higher stretching frequencies than O-D bonds ;and (3),since k increases with increasing bond order ,the relative stretching frequencies of carbon-carbon bonds lie in the order:
These generalisations are useful, and Eqs. 2.1and 2.2 allow an increased understanding of the empirical data that are subsequently presented in this chapter. You may often be able to
extend the use of the model in a way that will make it easier to understand the trends that are observed.However, because of the other variables that influence vibrational frequencies,the equations should be taken as no more than a frequently useful guide.
2.2Preparetion of samples and examination in an infrared spectrometer
Older spectrometers used a source of infrared light which had been split into two beams of equal intensity.Only one of these was passed through the sample, and the difference in intensities of the two beams was then plotted as a function of https://www.doczj.com/doc/8c15921781.html,ing this old technology,a scan typically took about 10 minutes . Most spectrometers in use today use a Fourier transform method,and the spectra are called Fourier transform infrared (FTIR) spectra. A source of infrared light , emitting radiation throughout the whole frequency range of the instrument,typically 4600-400cm-1,is again divided into two beams of equal intensity. Either one beam is passed through the sample , or both are passed,but one beam is made to traverse a longer path than the other . Recombination of the two beams produces an interference pattern that is the sun of all the interference patterns created by each wavelength in the beam.By systematically changing the difference into the paths,
the interference patterns change to produce a detected signal varying with optical path difference,as modified by the selective absorption by the sample of some frequencies. This pattern is known as the interferogram , and looks nothing like a spectrum . However Fourier transformation of the interferogram, using a computer built into the instrument, converts it into a plot of absorption against wavenumber just like that from the older method . There are several advantages to FTIR over the old method , and few whole spectrum is measured in at most a few seconds .Because it is not necessary to scan each wavenumber successively , the whole spectrum is measured in at most a few seconds.Because it is not dependent upon a slit and a prism or grating , high resolution in FTIR iseasier to obtain without sacrificing sensitivity.FTIR is especially useful for examining small samples (several scans can be added together ) and for taking the spectrum of compounds produced only for a short period in the outflow of a chromatograph. Finally,the digital form in which the data are handled in the computer allows for adjustment and refinement. For example,by subtracting the background absorption of the medium in which the spectrum was taken, or by subtracting the spectrum of a known impurity from that of a known impurity from that of a mixture to reveal the spectrum of the pure
component . However, the way in which infrared spectra are taken does not affect their appearance.The older spectra and FTIR spectra look very similar , and older spectra in the literature are still valuable for comparison . Compounds may be examined in the vapour phase , as pure liquids , in solution,and in the solid state.
In the vapour phase.The vapour is introduced into a cell ,usually about 10 cm long,which can then be placed directly in the path of one of the infrared beams.The end walls of the cell are usually made of sodium chloride , which is transparent to infrared in the usual range . Most organic compounds have too low a vapour pressure for this phase to be useful .
As a liquid.A drop of the liquid is squeezed between flat plates of sodium chloride (transparent through the 4000-625cm-1 region). This is the simplest of all produces. Alternatively,if the sample of the liquid is not suitable for dispensing as a drop , a solution in a volatile and dry solvent may be deposited directly onto the surface of a sodium chloride plate , and the solvent allowed to evaporate in a dry atmosphere to leave a thin film.
In solution. The compound is dissolved to give ,typically, a 1-5% solution in carbon tetrachloride or ,for its better solvent properties , alcohol-free chloroform . This solution is introduced
into a cell , 0.1-1 mm thick ,made of sodium chloride . A second cell of equal thickness , but containing pure solvent , is placed in the path of the other beam of the spectormeter in order that solvent absorptions should be balanced.Spectra taken in such dilute solutions in non-polar solvents are generally the most desirable ,because they are normally better resolved than spectra taken on solids, and also because intermolecular forces ,which are especially strong in the crystalline state, are minimised. On the other hand , many compounds are not soluble in non-polar solvents,and all solvents absorb in the infrared; when the solvent absorption exceeds about 65% of the incident light, useful spectra cannot be obtained because insufficient light is transmitted to work the detection mechanism efficiently . Carbon tetrachloride and chloroform , fortunately, absorb over 65% of the incident light only in those region(Fig.2.1)which are of little interest in diagnosis. Other solvents, of course , may be used but the areas of usefulness in each case should be checked beforehand, taking account of the size of the cell being used. In rare cases aqueous solvents are useful ; special calcium fluoride cells are then used.
In the solid state.About 1mg of a solid is finely ground in a small agate mortar with a drop of a liquid hydrocarbon （Nujol Kaydol）or ，if C-H vibration are to be examined ，with
hexachlorobutadiene. The mull is then pressed between highly polished flat plates of sodium chloride. Alternatively，the solid ，often much less than 1 mg ，is ground with 10-100 times its bulk of pure potassium bromide and the mixture pressed into a disc using a mould and a hydraulic press. The use of KBr eliminates the problem （usually not troublesome）of bands from the mulling agent and tends，on the whole ，to give rather almost always appears（see Fig.2.7）.Solids may alsobe deposited，either from a melt or ，as with liquids described above，by evaporation from a solution directly onto the surface of a sodium chloride plate ，with a sacrifice ，usually small ，from scattering off a crystalline surface.Because of intermolecular interactions，band positions in solid state spectra are offen different from those of the corresponding solution spectra. This is particularly true of those functional groups which take part in hydrogen bonding.On the other hand ，the number of resolve lines is often greater in solid state spectra，so that comparison of the spectra of，for example，synthetic and natural samples in order to determine identify is best done in the solid state. This is only true，of course，when the same crystalline modification is in use; racemic，synthetic material，for example，should be compared with enantiomerically pure，
nature material in solution.
2.3Examination in a Raman spectrometer
Raman spectra are generally taken on instruments using laser sources，and the quantity of material needed is now of the order of a few mg.A liquid or a concentrated solution is irradiated with monochromatic light，and the scattered light is examined by a spectometer using photoelectric detection.Most of the scattered light consists of the parent line produced by absorption and re-emission.Much weaker lines，which constitute the Raman spectrum，occur at lower and higher energy and are caused by absorption and re-emission of light coupled with vibrational excitation or decay，respectively.The difference in frequency between the parent line and the Raman line is the frequency of the corresponding vibration.Raman spectroscopy is not used by organic chemists routinely for structure determination，but for the detection of certain functional groups（see Fig.2.12）and for the analysis of mixtures-of deuterated compounds for example-it has found some use，especilly by analytical chemists.
2.4 Selection rules
If the frequency of a vibration of the sample molecule falls within the range of the instrument，the molecule may absorb energy of this frequency from the light，but only when the
oscillating dipole moment （from a molecular vibration）interacts with the oscillating electric vector of the infrared beam.
A simple rule for deciding if this interaction （and hence absorption of light）occurs is that the dipole moment at one extreme of a vibration must be different from the dipole moment at the other extreme of the vibration.In the Raman effect a corresponding interaction occurs between the light and the molecule's polarisability，resulting in different selection rules. The most important consequence of these selection rules is that in a molecule with a center of symmetry those vibrations symmetrical about the center of symmetry are active in the Raman and inactive in the infrared （see Fig.2.12）;those vibrations which are not centrosymmetric are inactive in the Raman and usually active in the infrared. This is doubly useful，for it means that that the two types of spectrum are complementary.Furthermore ，the more easily obtained，the infrared ，is the more useful ，because most functional groups are not centrosymmetric.The symmetry properties of a molecule in a solid can be different from those of an isolated molecule. This can lead to the appearance of infrared absorption bands in a solid state spectrum which would be forbidden in solution or in the vapour phase.
2.5The infrared spectrum
A complex molecule has many vibrational modes which involve the whole molecule.To a good approximation，however，many of these molecular vibrations are largely associated with the vibrations of individual bonds and are called localised vibrations.These localised vibrations are useful for the identification of functional groups，especially the sterching vibrations of O-H and N-H single bonds and all kinds of triple and double bonds，almost all of which occur with frequencies greater than 1500cm-1.The stretching vibrations of other single bonds，most bending vibrations and the soggier vibrations of the molecule as a whole give rise to a series of absorption bands at lower energy，blow 1500cm-1，the positions of which are characteristic of that molecule.The net result is a region above 1500cm-1 showing absorption bands assignable to a number of functional groups，and a region containing many bands，characteristic of the compound in question and no other compound，below 1500cm-1 .For obvious reasons，this is called the fingerprint region.
Fig.2.2shows a representative infrared spectrum，that of cortisone acetate1.It shows the strong absorption from the stretching vibrations above 1500cm-1 demonstrating the
presence of each of the functional groups：the O-H group，three different C＝O groups and the weaker absorption of the C＝C double bond ，as well as displaying a characteristic fingerprint below 1500cm-1.
By convention absorbance is plotted downwards，opposite to the convention for ultraviolet spectra，but the maxima are still called peaks or bands.Rotational fine structure is smoothed out，and the intensity is frequently not recorded.When intensity is recorded，it is usually experssed subjectively as strong（s），medium（m），or weak（w）.To obtain a high-quality spectrum，the quantity of substance is adjusted so that the strongest peaks absorb something close to 90% of the light.The scale on the abscissa is linear in frequency，but most instruments change the scale，either at 2200cm-1 or at 2000cm-1 to double the scale at the low-frequency end .The ordinate is linear in percent transmittance，with 100% at the top and 0% at the bottom.
The regions in which the different functional groups absorb are summarised below F.2.2.The stretching vibrations of single bonds to hydrogen give rise to the absorption at the high-frequency end of the spectrum as a result of the low mass of the hydrogen atom，making it easy to detect the presence of O-H and N-H groups.Since most organic compounds have C-H
bonds，the absorption close to 3000cm-1 is rarely usefully although C-H bonds attached to double and triple bonds van be usefully identified. Thereafter，the order of stretching frequencies follows the order：triple bonds at higher frequency than double bond between two similar atoms the higher the frequency of the vibration.Bending vibrations are of lower frequency and usually appear in the fingerprint region below 1500cm-1，but one exception N-H bending vibration，which appears in the 1600-1500cm-1 region.Polysyrene is sometimes used to provide accurately placed calibration lines at 2924，1603，1028，and 906cm-1.
Although many absorption bands are associated with the vibrations of individual bonds，other vibrations are coupled vibrations of two or more components of the whole molecule .Whether localised or not ，stretching vibrations are given the symbol v，and the various bending vibrations are given the symbol o.Coupled vibrations may be subdivided into asymmetric and symmetric stretching，and the various bending modes into scissoring ，rocking ，wagging and twisting，as defined for a methylene group in Fig.2.3. A coupled asymmetric and symmetric stretching pair is also found with many other groups，like carboxylic anhydrides，carboxylate ions and nitro
groups，each of which has two equal bonds close together.
2.6 The use of the tables of characteristic group frequencies Reference charts and tables of data are collected together at the end of this chapter for ready reference.Each of the three frequency ranges above 1500cm-1 shown in Fig.2.2 is expanded to give more detail in Charts 1-4 in Sec.2.1
3.Thesa charts summarise the narrower ranges within which each of the functional groups absorbs.The absorption bands which are found in the fingerprint region and which are assignable to functional groups are occasionally useful，either because they are sometimes strong bands in otherwise featureless regions or because their absence may rule out incorrect structures，but such identifications should be regarded as helpful rather than as definitive，since there are usually many bands in this area. Tables of detailed information can be found in Sec.2.14 at the end of this chapter，arranged by functional groups roughly in descending order of their stretching frequencies.
One could deal with the spectrum of an unknown as follows. Examine each of the three main regions of the spectrum above the fingerprint regions of the spectrum above the fingerprint region，as identified on Fig.2.2; at this stage certain combinations of structures can be ruled out --the absence of O-H
or C＝O ，for example --and some tentative conclusions reached.Where there is still ambiguity --which kind of carbonyl group，for example -the tables corresponding to those groups that might be present should be consulted.It is important to be sure that the bands under consideration are of the appropriate intensity for the structure suspected.A weak signal in the carbonyl region，for example，for example ，it is more likely to be an overtone or to have been produced by an impurity.
The text following this section amplifies some of the detail for each the main functional groups，and shows the appearance，sometimes characteristic，of several of the functional groups，and shows the appearance，sometimes characteristic，of several of the bands.Cross-reference to the tables at the end is inevitable and will need to be frequent.
2.7 Absorption frequencies of single bonds to hydrogen 3600-2000
cm-1
C-H Bonds. The precise position of the various CH，CH2，and CH3 symmetrical and unsymmetrical vibration frequencies are well known.C-H bonds do not take part in hydrogen bonding and so their position is little affected by the state of measurement or their chemical environment.C-C vibrations，
which absorb in the fingerprint region，are generally weak and not practically useful . Since many organic molecules possess saturated C-H bonds，their absorption bands，stretching in the 3000-2800cm-1 region and bending in the fingerprint region，are of little diagnostic value，but a few special structral features in saturated C-H groupings do give rise to characteristic absorption bands（Table 2.1）.Thus，methyl and methylene groups usually show two sharp bands from the symmetric and asymmetric stretching（Fig.2.3），which can sometimes be picked out but the general appearance of the accumulation of all the saturated C-H stretching vibrations often leads to broader and not fully resolved bands like those illustrated in many of the spectra below . The absence of saturated C-H absorption in a spectrum is ，of course，diagnostic evidence for the absence of such a part structure in the corresponding compound. Unsaturated and aromatic C-H stretching frequencies （Table 2.1）can be distinguished from the saturated C-H absorption，since they occur a little above 3000cm-1 and are relatively weak，as in the spectrum of ethyl benzoate 2（Fig.2.4）and benzonitrile 14（Fig.2.7）.Terminal acetylenes give rise to a characteristic strong，sharp line close to 3300cm-1 from ￥C-H stretching，as in the spectrum of hexyne3（Fig.2.4），and ethers and amines
also show bands in the low-frequency region 2850-2750cm-1.When the antiperiplanar arrangement is rigidly fixed ，as in axially-oriented C-H bonds in six-membered cyclic amines，C-H stretching has an unusually low frequency，giving rise to absorption known as Bohlmann bands.
The C-H bending vibrations are in the fingerprint region，with methine C-H bending and CH3 and CH2 symmetrical bending giving rise in many organic compounds to two bands close to 1450and 1380cm-1，as seen in the common mulling agent Nujol.The out-of -plane vibration of trans-C＝CH- diuble bonds is one of the more usefully diagnostic bending vibrations .It occurs in a narrow range 970-960cm-1，or at slightly higher frequency if conjugated ，and it is always strong.In contrast，the corresponding vibration of the cis isomer is of lower intensity and at lower frequency，typically in the range 730-675cm-1.The band at 975cm-1in the fingerprint of ethyl trans-crotonate5（Fig.2.4）clearly shows that such a feature may be present ;if it were not there，it would be diagnostic of the absence of this feature，as in the spectrum of the cis-alkene 20 in Fig.2.12
新编新人教版PEP小学六年级英语上册全册课课练一课一 练习题及答案 小学英语六年级上册堂堂清训练题 Unit 1 How can I get there? 第一课时 一、看图写出相应的单词或短语 ___________________ ________________ ____________________ ______________________ _______________________ 二、对话排序 ( )Sure ( )Excuse me. Can you help me? ( )Thanks ( )How can I get to the science museum? ( )It’s over there 第二课时
一、根据首字母填入合适的单词 1、 There are many books in the b_______. 2、 Some robots are in the s________ m________. 3、 I want to go to the c________. 4、 Where is the h________? It’s n______ to the school. 二、选出不同类的单词 ( )1、A. science B. math C. book D. Chinese ( )2、A. bookstore B. science C. museum D. cinema ( )3、A. talking B. sing C. running D. jumping ( )4、A. hospital B. ten C. park D. zoo ( )5、A. Sarah B. John C. robot D. Am 第三课时 一、选出各单词缺少的字母或字母组合 ( )1、cro___ing A.oo B.ss C.os D.es ( )2、t___n A.tu B.ur C.ru D.un ( )3、s__r A.o B.i C.a D.e ( )4、__sk A.o B.i C.a D.e ( )5、ri___t A.gg B.ht C.gh D.ge 二、根据汉语提示，写出英语单词 1. We can send a letter in the _______________.(邮局) 2. We can see the films at the ______________.(电影院) 3. If you are sick, we should go to the __________.(医院) 4. We can buy some books in the _____________.(书店) 第四课时 一、连线
英语词汇学 第一部分选择题 I. Each of the statements below is followed by four alternative answers .Choose the one that would best complete the statement and put the letter in the bracket（30％） 1. Degradation can be illustrated by the following example[ ] A. lewd → ignorant B. silly → foolish C. last → pleasure D. knave → boy 2. Homophones are often employed to create puns for desired effects of: [ ] A. humour B. sarcasm C. ridicule D. all the above 3. The four major modes of semantic change are _____. [ ] A. extension, narrowing, elevation and degradation B. extension, generalization, elevation and degradation C. extension, narrowing, specialization and degradation D. extension, elevation, amelioration and degradation 4. The use of one name for that of another associated with it is rhetorically called _____. [ ] A. synecdoche B. metonymy C. substitution D. metaphor 5. Idioms adjectival in nature function as _____. [ ] A. adjectives B. attributes C. modifiers D. words 6. Grammatical context refers to _____ in which a word is used. [ ] A. vocabulary B. grammar C. semantic pattern D. syntactic structure 7. In the idiom 'in good feather', we change 'good' into 'high, full' without changing meaning. This change of constituent is known as _____ . [ ] A. addition B. replacement C. position-shifting D. variation 8. The word "laconic" is _____. [ ] A. onomatopoeically motivated B. morphologically motivated C. semantically motivated D. etymologically motivated 9. CCELD is distinctive for its _____. [ ] A. clear grammar codes B. language notes
. 六年级下册课课练答案 Answer key Unit 1 Period 1 A 1 a 2 a 3 b 4 b B 1 T 2 T 3 F 4 F 5 T C was, large/big, strong, wanted, help, weak, let, caught, bit, saw, made, got, became Period 2 A 略 B 1 a 2 b 3 a 4 a 5 a C 1 f 2 9 3 d 4 b 5 c 6 h 7 a 8 e D happy, good, well, loudly, sadly, happy E help, happened, caught, worry, bite, made, get, out F 1 c 2 a 3 c 4 c 5 a 6 b Period 3 A 略 B 1 T 2 F 3 T 4 F 5 T C 1 excitedly 2 loudly 3 visited, was 4 did, get 5 sadly, find D a 4 b 2 c l d 3 E 1 b 2 a 3 c 4 c 5 c Period 4 A 略 B sad, hungry, fast, high, loudly, bite, strong, great C 1 e 2 c 3 b 4 a 5 d D 1 a 2 b 3 c 4 b 5 a 6 b E 1 singing, happily 2 talk, loudly, library 3 poured, hot, water, into, gave 4 From, then, on, became, friends F 1 F 2 T 3 F 4 T 5 T Unit 2 Period 1 A 1 b 2 b 3 b 4 a B 1 T 2 F 3 T 4 F 5 T C good, listens, clean, tidy, helps, bad, late, bed, sleepy Period 2 A 略 B 1 T 2 F 3 T 4 T 5 F C 1 early 2 tidy 3 fast 4 sleepy 5 in order D Wake, sleepy, late, exciting, early E 1 F 2 T 3 F 4 F 5 T Period 3 A 略
《英语词汇学》课程习题集 一、单选题 1. The word “humorousness” has _______ morphemes. A. one B. two C. three D. four 2. The word “nationalize” has _______ morphemes. A. one B. two C. three D. four 3. The word “decoding” has _______ morphemes. A. one B. two C. three D. four 4. Which of the following forms is not an allomorph of the morpheme “in-”? A. ig- B. ir- C. il- D. im- 5. Which of the following forms does not contain an allomorph of the inflectional morpheme of plurality? A. books B. pigs C. horses D. expense 6. According to ______, there is an intrinsic correspondence between sound and sense. A. naturalists B. anthropologists C. linguists D. conventionalists 7. According to ______ , there is not a logical connection between sound and sense. A. naturalists B. anthropologists C. linguists D. conventionalists 8. Most English words are _________ symbols. A. definite B. arbitrary C. infinite D. hereditary 9. From the point of view of ________, a direct connection between the symbol and its sense can be readily observed in a small group of words. A. nationalism B. anthropology C. linguistics D. motivation 10. Words motivated phonetically are called _________ words. A. onomatopoeic B. similar C. natural D. symbolic 11. In the sentence “John was asked to spy the enemy”, “spy” is considered an example of the word-formation process using _________. A. compounding B. derivation C. conversion D. acronym 12. In the sentence “John was doctored by Mr. Smith in the hospital”, “doctor” is considered an example of the word-formation process using _________. A. compounding B. derivation C. conversion D. acronym 13.In the sentence “John was asked to get into the office after a two-hour wait”, “wait”is considered an example of the word-formation process using _________. A. compounding B. derivation C. conversion D. acronym 14. In the sentence “John decided to nurse his sister himself”, “nurse” is considered an example of the word-formation process using _________. A. compounding B. derivation C. conversion D. acronym
第四节各类有机化合物红外吸收光谱 σ伸缩振动，δ面内弯曲振动，γ面外弯曲振动 一、烷烃 饱和烷烃IR光谱主要由C-H键的骨架振动所引起，而其中以C-H键的伸缩振动最为有用。在确定分子结构时，也常借助于C-H键的变形振动和C-C 键骨架振动吸收。烷烃有下列四种振动吸收。 1、σC-H在2975—2845 cm-1范围，包括甲基、亚甲基和次甲基的对称与不对称伸缩振动 2、δC-H在1460 cm-1和1380 cm-1处有特征吸收，前者归因于甲基及亚甲基C-H的σas，后者归因于甲基C-H的σs。1380 cm-1峰对结构敏感，对于识别甲基很有用。共存基团的电负性对1380 cm-1峰位置有影响，相邻基团电负性愈强，愈移向高波数区，例如，在CH3F中此峰移至1475 cm-1。 异丙基1380 cm-1裂分为两个强度几乎相等的两个峰1385 cm-1、1375 cm-1叔丁基1380 cm-1裂分1395 cm-1、1370cm-1两个峰，后者强度差不多是前者的两倍，在1250 cm-1、1200 cm-1附近出现两个中等强度的骨架振动。 3、σC-C在1250—800 cm-1范围内，因特征性不强，用处不大。 4、γC-H分子中具有—（CH2）n—链节，n大于或等于4时，在722 cm-1有一个弱吸收峰，随着CH2个数的减少，吸收峰向高波数方向位移，由此可推断分子链的长短。 二、烯烃 烯烃中的特征峰由C=C-H键的伸缩振动以及C=C-H键的变形振动所引起。烯烃分子主要有三种特征吸收。 1、σC=C-H烯烃双键上的C-H键伸缩振动波数在3000 cm-1以上，末端双键氢 C=CH2 在3075—3090 cm-1有强峰最易识别。 2、σC=C吸收峰的位置在1670—1620 cm-1。随着取代基的不同，σC=C吸收峰的位置有所不同，强度也发生变化。 3、δC=C-H烯烃双键上的C-H键面内弯曲振动在1500—1000 cm-1，对结构不敏感，用途较少；而面外摇摆振动吸收最有用，在1000—700 cm-1范围内，该振动对结构敏感，其吸收峰特征性明显，强度也较大，易于识别，可借以判 1
英语词汇学 (English Lexicology) 课程编号：05100290课程性质：专业选修课 总学分：2 总学时：36 一课程目的及要求： 英语语言文学专业必修课或选修课。英语词汇学是一门以当代语言学多种理论为指导，全面深入研究英语词汇的专业课程。英语词汇学课程重在揭示现代英语词汇的普遍规律，侧重分析研究现代英语词汇现象，兼顾英语词汇的纵向演变和发展。 本课程旨在帮助英语专业高年级学习者强化英语词汇知识，系统地了解现代英语词汇的过去和现状，把握英语词汇学习与使用的规则和特点。既要培养学生理解语言现象和分析语言问题的理论水平，又要提高学生运用英语的实际能力。二、课程主要内容： 英语词汇学导言（词汇学的性质、重要性、学习方法） 词的基本知识（词和词汇的定义与区别，声音与意义和拼写之间的关系，词汇划分的基本原则及各类词的主要特点） 英语词汇的形成与发展（英语的亲属关系，英语词汇形成和发展的三个时期及其特点，现代英语词汇发展的趋势和方式） 英语构词法I （词的个构成成分，各成分之间的区别，对词进行结构分析）英语构词法II （现代英语主要构词法，这些构词法在英语词汇发展中的地位） 词的意义（了解“意义”的不同含义，词义的理据，几种常见意义） 语义关系和语义场（词与词之间的几种主要语义关系，它们的概念和特点）词义的演变（词义变化的必然性，词义变化的主要方式，词义变化的原因）词义与语境（两种不同的语境，语境对词义的重要作用） 英语习语（英语习语的概念、范畴、特点及其分类原则，习语的作用） 英语词典（不同类型词典的形式、内容、范围及特点） 三、教学方式 以讲解为主，在教学过程中采用研究型教学方式，在讲授基本的词汇学概念和原理之后引导学生进行课堂讨论，课后查阅资料，收集语料，描写语言和分析语言等活动，同时指定阅读材料并作课堂汇报。 四、主要教学参考书： 教材：自编 参考书目： 1. 陆国强：《现代英语词汇学》，上海外语教育出版社，1999 2. 汪榕培、卢晓娟：《英语词汇学教程》，上海外语教育出版社，1997 3. 张维友：《英语词汇学》，外语教学与研究出版社，2000 4. 张韵斐，周锡卿：《现代英语词汇学概论》，北京师范大学出版社，1988 5. 张永言，《词汇学简论》，华中工学院出版社，1982 6．拉耶芙斯卡娅，《英语词汇学引论》，商务印书馆，1960
新编新人教版PEP小学六年级英语上册全册课课练一课一练习题及答案 小学英语六年级上册堂堂清训练题 Unit 1 How can I get there? 第一课时 一、看图写出相应的单词或短语 ___________________ ________________ ____________________ ______________________ _______________________ 二、对话排序 ( )Sure ( )Excuse me. Can you help me? ( )Thanks ( )How can I get to the science museum? ( )It’s over there 第二课时 一、根据首字母填入合适的单词
1、 There are many books in the b_______. 2、 Some robots are in the s________ m________. 3、 I want to go to the c________. 4、 Where is the h________? It’s n______ to the school. 二、选出不同类的单词 ( )1、A. science B. math C. book D. Chinese ( )2、A. bookstore B. science C. museum D. cinema ( )3、A. talking B. sing C. running D. jumping ( )4、A. hospital B. ten C. park D. zoo ( )5、A. Sarah B. John C. robot D. Am 第三课时 一、选出各单词缺少的字母或字母组合 ( )1、cro___ing A.oo B.ss C.os D.es ( )2、t___n A.tu B.ur C.ru D.un ( )3、s__r A.o B.i C.a D.e ( )4、__sk A.o B.i C.a D.e ( )5、ri___t A.gg B.ht C.gh D.ge 二、根据汉语提示，写出英语单词 1. We can send a letter in the _______________.(邮局) 2. We can see the films at the ______________.(电影院) 3. If you are sick, we should go to the __________.(医院) 4. We can buy some books in the _____________.(书店) 第四课时 一、连线
《英语词汇学教程》（2004年版）练习答案 【Chapter 1】 7．tart: loose woman bloke: fellow gat: pistol swell: great chicken: coward blue: fight smoky: police full: drunk dame: woman beaver: girl 8. haply = perhaps albeit = although methinks = it seems to me eke = also sooth = truth morn = morning troth = pledge ere = before quoth = said hallowed = holy billow = wave/ the sea bade = bid 【Chapter 2】 Ex.1 The Indo-European Language Family is one of the most important language families in the world. It is made up of most of the languages of Europe, the Near East and India. English belongs to this family and the other members of the Indo-European have more or less influence on English vocabulary. A knowledge of the Indo-European Language Family will help us understand English words better and use them more appropriately. 2. Indo-European Language Family Balto-Slavic Indo-Iranian Celtic Italian Hellenic Germanic
仪器分析实验有机化合物的红外光谱分析 2015年4月21日 有机化合物的红外光谱分析 开课实验室：环境资源楼312 【实验目的】 1、初步掌握两种基本样品制备技术及傅里叶变换光谱仪器的简单操作； 2、通过谱图解析及网上标准谱图的检索，了解由红外光谱鉴定未知物的一般过程； 3、掌握有机化合物红外光谱测定的制样方法，回顾基础有机化学光谱的相关知识。 【基本原理】 ? 原理概述：物质分子中的各种不同基团，在有选择地吸收不同频率的红外辐射后，发生振动能级之间的跃迁，形成各自独特的红外吸收光谱。据此，可对物质进行定性和定量分析。特别是对化合物结构的鉴定，应用更为广泛。 ? 红外吸收法： 类型：吸收光谱法； 原理：电子的跃迁：电子由于受到光、热、电等的激发，从一个能级转移到另一个能级的现象。这是因为分 子中的电子总是处在某一种运动状态中，每一种状态都具有一定的能量，属于一定的能级。当这些电子有选择地吸收了不同频率的红外辐射的能量，发生振动能级之间的跃迁，形成各自独特的红外吸收光谱。据此，可对化合物进行定性和定量分析； 条件：分子具有偶极矩。 【仪器与试剂】 1、仪器： 傅里叶变换红外光谱仪（德国Bruker公司，TENSOR 27型; 美国Thermo Fisher 公司， Nicolet 6700型）；压片机； 玛瑙研钵； 红外灯。 2、试剂：NaCl窗片、KBr晶体，待分析试样液体及固体。 【实验步骤】 1、样品制备 （1）固体样品：KBr压片法 在玛瑙研钵将KBr晶体充分研磨后加入其量5%左右的待测固体样品，混合研磨直至均匀。在一个具有抛光面的金属模具上放一个圆形纸环，用刮勺将研磨好的
小学英语六年级下册课课练答案 【篇一：新人教版pep六年级下册英语全册课课练习题 集】 txt>unit 1 how tall are you? 第一课时 一、判断每组单词是（t）否（f）同类。 （）1.a.youngb.tall c. old （）2.a.smallb.big c. than （）3.a.meterb.hall c. short （）4.a.meb.you c. him （）5.a.long b.taller c.old 二、按要求完成下列各题。 1.迈克比约翰更高。（根据汉语完成句子） mike is ________ than john. 2.the tallestthatis hall this dinosaur in ( ______________________________________________ 3.she is 1.64 meters. (对画线部分提问) _________ _________ is she? 第二课时 一．根据首字母填入合适的单词 1. this pencil is l_______ than that one. 2. this skirt is s________ than that one. 3. my father is o_____ than my mother. 4. i’m t______ than my brother. 5. i’m ten years old. i’m y_______ than you. 二．对话排序 （）1.i’m 1.61 meters. 连词成句) （）2.oh!i’m taller. （）3.how tall are you? （）4.you’re older than me too. 第三课时 一、根据图片提示填空。 1.a：what _______ are your shoes? b: my shoes are size 38. 2.a:i wear size 35 shoes.
第五章 词汇： reference n.所指 Concept n.概念 identical adj. 同一的；完全相同的 Motivation 理据 Onomatopoeic 拟声的 echoic 拟声的 morphological 形态的 opaque adj. 不透明的；不传热的；迟钝的 literal adj. 文字的；逐字的；无夸张的 figurative 形态的 associations 联想 Etymological 词源 monogamous 单配的 constant adj. 不变的 indeterminate 不确定的 archaic 旧的 Interjections 感叹词 overlaps n. 重叠部分 revealed v. 透露 要点： 一. 1.Reference –the relationship between language and the world.(cat,"she""annimal"ect.) ｛The reference of a word to a thing outside the language is a rbitrary and conventional. This connection is the result of generalization and abstraction. Although reference is abstract，yet with the help of context， it can refer to something specific. ｝
2.Concept–which beyond language, is the result of human cognition,reflecting the objective world in the human mind. It isn’t affected by language. Meaning and concept are closely connected but not identical. Meaning belongs to language，so is restricted to language use. A concept can have as many referring expressions as there are language in the world. 3.Sense – (the meaning of meaning.) denotes the relationship inside the language. Every word that has meaning has sense. The sense of an expression is its place in a system of semantic relationships with other expressions in the language. It is also abstraction. 二.Motivation-accounts for the connection between the linguistic symbol and its mean ing. English does have words whose meanings can be explained to a certain extent. Most words are non-motivated. The connection of the sign and meaning dose not have a logical explanation. 1.Onomatopoeic Motivation – the words whose sounds suggest their meaning. （Indicate the relationship between sound and meaning）. Knowing the sounds of the words means understanding the meaning. These words we created by imitating the natural sounds or noises. (For example，bang，ping-pang，crow by cocks，etc. ) Such echoic words are also conventional for the sounds we say in English may not be the same in other language.
第一章word 1.Word --- A word is a minimal free form of a language that has a given sound and meaning and syntactic funtion. 第三章formation 1 1. Morpheme --- A morpheme is the smallest functioning unit in the composition of words. 2. Allomorph --- Some morphemes are realized by more than one morph according to their position in a word. Such alternative morphs are know as allomorphs. 3. Free morphemes (Free root) --- They are morphemes which are independent of other morphemes. 4. Bound Morphemes--- They are morphemes which cannot occur as separate words. 5. Bound root --- A bound root is that part of the word that carries the fundamental meaning just like a free root. Unlike a free root, it is a bound form and has to combine with other morphemes to make words. 6. Affixes --- Affixes are forms that are attached to words or word elements to modify meaning or function. 7. Inflectional affixes --- Affixes attaches to the end of words to indicate grammatical relationships are known as inflectional morphemes. 8. Derivational affixes --- Derivational affixes are affixes added to other morphemes to create new words. 9. Prefixes --- Prefixes are affixes that come before the word. 10. Suffixes --- suffixes are affixes that come after the word. 11. Roo t --- A root is the basic form of a word which cannot be further analysed without total loss of identity. 12. Stem--- a stem can be defined as a form to which affixes of any kind can be added. 第四章formation 2 1. Affixation --- affixation is generally defined as the formation of words by adding word-forming or derivational affixes to stems. 2. Prefixation --- is the formation of new words by adding prefixes to stems. Suffixation--- is the formation of new words by adding suffixes to stems. 3. Compounding（Compositon）-- is the formation of new words by joining two or more stems. 4. Conversion-- is the formation of new words by converting words of one class to another class. 5. Blending-- is the formation of new words by combined by parts of two words or a word plus a plus a part of another word. 6. Clipping- is the formation of new words by shortening a longer word by cutting a
全国高等教育自学考试 英语词汇学试题 课程代码：00832 Ⅰ．Each of the statements below is followed by four alternative answers. Choose the one that best completes the statement and put the letter in the bracket.（30%）1．According to semanticists, a word is a unit of ______.（） A．meaning B．Sound C．combination of sounds D．Group 2．The pronunciation has changed ______ spelling over the years.（） A．more slowly than B．As quickly as C．more rapidly than D．Not so quickly as 3．Words may fall into the basic word stock and nonbasic vocabulary by ______.（）A．use frequency B．notion C．origin D．sound 4．Rapid growth of science and technology breeds such new words as the following EXCEPT______.（） A．green revolution B．fast food C．moon walk D．space shuttle 5．Semantic change means an old form which takes on a new ______ to meet the new need. （）A．form B．meaning C．look D．pronunciation 6．Reviving archaic words also contribute to the growth of English vocabulary. For instance, in American English “fall” means ______ in British English.（） A．four B．fell C．for D．autumn 7．The plural morpheme “-s” is realized by /s/after the following sounds EXCEPT ______. （）A．/t/ B．/g/ C．/p/ D．/k/ 英语词汇学试卷第 1 页共9 页
Answer key Unit 1 Period 1 A 1 a 2 a 3 b 4 b B 1 T 2 T 3 F 4 F 5 T C was, large/big, strong, wanted, help, weak, let, caught, bit, saw, made, got, became Period 2 A 略 B 1 a 2 b 3 a 4 a 5 a C 1 f 2 9 3 d 4 b 5 c 6 h 7 a 8 e D happy, good, well, loudly, sadly, happy E help, happened, caught, worry, bite, made, get, out F 1 c 2 a 3 c 4 c 5 a 6 b Period 3 A 略 B 1 T 2 F 3 T 4 F 5 T C 1 excitedly 2 loudly 3 visited, was 4 did, get 5 sadly, find D a 4 b 2 c l d 3 E 1 b 2 a 3 c 4 c 5 c Period 4 A 略 B sad, hungry, fast, high, loudly, bite, strong, great C 1 e 2 c 3 b 4 a 5 d D 1 a 2 b 3 c 4 b 5 a 6 b E 1 singing, happily 2 talk, loudly, library 3 poured, hot, water, into, gave 4 From, then, on, became, friends F 1 F 2 T 3 F 4 T 5 T Unit 2 Period 1 A 1 b 2 b 3 b 4 a B 1 T 2 F 3 T 4 F 5 T C good, listens, clean, tidy, helps, bad, late, bed, sleepy Period 2 A 略 B 1 T 2 F 3 T 4 T 5 F C 1 early 2 tidy 3 fast 4 sleepy 5 in order D Wake, sleepy, late, exciting, early E 1 F 2 T 3 F 4 F 5 T Period 3 A 略 B 1 a 2 a 3 a 4 b 5 b
英语词汇学试卷 第1页共9页 全国高等教育自学考试 英语词汇学试题 课程代码：00832 I. Each of the stateme nts below is followed by four alter native an swers. Choose the one that best completes the stateme nt and put the letter in the bracket. 1. According to semanticists, a word is a unit of ______ . ( ) A . meaning B . Sound C . comb in ati on of sounds 2. The pronunciation has changed ______ spelling over the years.( ) (30% ) D . Group A . more slowly than C . more rapidly than B. As quickly as D . Not so quickly as
3. Words may fall into the basic word stock and non basic vocabulary by _____ . ( ) A . use frequency B. notion C. origin D. sound 4 . Rapid growth of scie nee and tech no logy breeds such new words as the follow ing EXCEPT _____ .( _________________ ) A . gree n revoluti on B . fast food C . moon walk D . space shuttle 5 . Sema ntic cha nge means an old form which takes on a new _____ t o meet the new n eed. A . form B . mea ning C . look D . pronun ciati on 6 . Revivi ng archaic words also con tribute to the growth of En glish vocabulary. For in sta nee, in American English “all" means ______ in British English.( ) A . four C . for B . fell D . autu mn 7 . The plural morpheme “s" is realized by /s/after the following sounds EXCEPT _____ . ( ) A . /t/ B . /g/ C . /p/ D . /k/ 英语词汇学试卷第2页共9页