Preparation and Crystallization of Poly(ethylene terephthalate)/SiO2Nanocomposites by In-Situ Polymerization
Yongzhe Yang,Hong Xu,Hongchen Gu
National Key Laboratory of Nano/Micro Fabrication Technology,Key Laboratory for Thin Film and Microfabrication of Ministry of Education,Institute of Micro and Nano Science and Technology,Shanghai Jiaotong University,Shanghai 200030,China
Received22September2005;accepted17January2006
DOI10.1002/app.24500
Published online in Wiley InterScience(https://www.doczj.com/doc/858448701.html,).
ABSTRACT:Poly(ethylene terephthalate)(PET)/SiO2nano-composites were prepared by in situ polymerization.The dis-persion and crystallization behaviors of PET/SiO2nanocom-posites were characterized by means of transmission electron microscope(TEM),differential scanning calorimeter(DSC), and polarizing light microscope(PLM).TEM measurements show that SiO2nanoparticles were well dispersed in the PET matrix at a size of10–20nm.The results of DSC and PLM,such as melt-crystalline temperature,half-time of crystallization and crystallization kinetic constant,suggest that SiO2nanoparticles exhibited strong nucleating effects.It was found that SiO2 nanoparticles could effectively promote the nucleation and crystallization of PET,which may be due to reducing the speci?c surface free energy for nuclei formation during crys-tallization and consequently increase the crystallization rate.?2006Wiley Periodicals,Inc.J Appl Polym Sci102:655–662,2006
Key words:crystallization;in situ polymerization;nanocom-posites;poly(ethylene terephthalate)
INTRODUCTION Crystallization process of poly(ethylene terephthalate) (PET)has recently been widely reinvestigated due to the increasing technological interest.It is well-known that PET is a semicrystalline thermoplastic with excel-lent mechanical,physical,and chemical properties, including excellent chemical and heat resistance,high stiffness and strength,and good dimensional stability. These properties make PET an attractive high perfor-mance polymer for engineering plastic applications in areas of electronics,transportation,construction,and consumer products.1However,PET applied as an en-gineering plastic for injection molding is rather lim-ited,due to its slow crystallization rate and large cycle time compared with poly(butylenes terephthalate).2–7 Because of the cost advantage offered by PET,many efforts have been made to search for nucleation agents.Ionomers,polymers,inorganic,and organic compounds have been reported as the candidates.2–6 A survey of the recent literature indicates an apparent consensus,according to which sodium benzoate has been used as an effective nucleation agent for PET.8–10 However,it was also observed that PET was degraded by the salt under processing conditions.
In this study,we have demonstrated that it is pos-sible to control the crystallization behavior of PET by inorganic nanoparticles,which have been paid little attention before.Table I shows some recent polymer-based nanocomposites prepared via:(a)the sol–gel technique;(b)in-situ intercalative polymerization;(c) in-situ polymerization;(d)melt mixing.11Direct melt mixing method has received only limited effects on crystallization,due to the high tendency of agglomer-ation of nanoparticles during blending.12–14Con-versely,in situ polymerization has been proved to provide nanocomposite with novel properties.15–20 This study adopted in situ polymerization for realizing real nanocomposites by nanoscale.The methodology consists of dispersing the inorganic nanoparticles into the monomers;then the mixture is polymerized by adding the catalyst and stabilizing agent under certain condition.To promote the compatibility between or-ganic/inorganic components and improve the homo-geneous dispersion of the nanoparticles into the poly-meric matrix,the nanoparticles can be further treated with a coupling agent.The crystallization of PET,both unnucleated and nucleated with SiO2nanoparticles, has been studied under isothermal and nonisothermal conditions by DSC and PLM.
Correspondence to:H.Gu(hcgu@https://www.doczj.com/doc/858448701.html,).
Contract grant sponsor:Key Science-Technology Project; contract grant number:2001BA310A10.
Contract grant sponsor:Shanghai Nano Technology Project of China;contract grant numbers:0213nm002, 0352nm023.
Journal of Applied Polymer Science,Vol.102,655–662(2006)?2006Wiley Periodicals,Inc.
EXPERIMENTAL
Materials
Nano-SiO2with average particle size of10nm was supplied by Yuda Chemical Co.(Zhejiang,China). Ethylene glycol(EG),terephthalic acid,trimethyl phosphate,Sb2O3(as catalyst),and organosilane cou-pling agent A-187were supplied by Chemical Re-agents Co.(China).
Preparation of the SiO2/ethylene glycol sol
About2.4g of organosilane coupling agent A-187was dissolved in100mL water and heated at60–70°C for 20min.The solution was added dropwise to100g25 wt%SiO2/H2O sol,maintaining the?ow rate at10 mL/min.Then,the modi?ed SiO2was transferred from water to ethylene glycol by rotatory evaporation. The dispersion of25g of modi?ed SiO2in a100mL of ethylene glycol solution was added to another100mL of ethylene glycol,which was heated at80–120°C. Similarly,the?ow rate was controlled at10mL/min. The mixture was stirred vigorously for30min. Preparation of PET/SiO2nanocomposites by in situ polymerization
PET pellets with varied content of SiO2were prepared by the PTA route.In a5-L cylindrical reactor,1kg of EG(16.1mol)and varied content of SiO2were placed; the mixture was stirred for0.5h at room temperature.Then,2kg of terephthalic acid(12.0mol),a few drops of trimethyl phosphite,and some Sb2O3were added, with vigorous stirring to obtain a homogeneously dis-persed system.The mixture was then heated in nitro-gen atmosphere from room temperature to250–260°C under a pressure of0.3MPa.After completed esteri-?cation,the pressure was reduced to air pressure to emit the water generated during the esteri?cation. Then,the polymerization was carried on at260–270°C under a pressure of200–300Pa to drain out the excess EG.Afterward,the pressure was controlled to less than40Pa.After1–2h polycondensation,the melting polymer was extruded through an ori?ce at nitrogen pressure of0.3MPa and cooled with water. Characterization
PET/SiO2nanocomposite specimens were sliced at ?80°C with an Ultracut Uct microtome.A transmis-sion electron microscope operated at75kV was used to obtain images of the nanocomposites specimens. Before TEM experiment,specimens were annealed in a vacuum oven at100°C for1week to remove mois-ture completely.
The crystallization behaviors of the samples were examined using PerkinElmer differential scanning cal-orimetry system DSC-2C.During isothermal crystalli-zation experiments,samples were heated at50°C/min to300°C,and maintaining there for5min to eliminate the thermal and shear history effects,and then
TABLE I
Recent Polymer-Based Nanocomposite Systems11
Systems Uses
Sol–gel technique
Polycaprolactone(PCL)/silica(TEOS)Bone-bioerodible polymer composites for skeletal tissue repair Polyimide/silica(TEOS)Micro-electronics
PMMA/silica Dental application,optical devices
Polyethylacry(PEA)/silica Catalysis support,stationary phase for chromatography
Poly(amide-imide)/TiO2Composite membranes:gas-separation applications
In situ interculative polymerization
iPP/organoclay Improved properties
Starch/organo-modi?ed
montmorillonite
Enhanced barrier properties
Nylon/organ-modi?ed montmorillonite Improvement of structural,mechanical,thermal and barrier
characteristics without signi?cant loss in clarity or strength
In situ polymerization
Nylon6/silica and CaCO3Improvement of structural,mechanical,thermal and barrier
characteristics without signi?cant loss in clarity or strength Polyimide/AlN Materials for microelectronics with reduced thermal expansion
coef?cient and moisture absorption
PMMA/CaCO3Biocompatible materials and optical devices
PET/SiC Improved properties
Melt mixing
Polyethylene/graphite Applications in electrical or thermal conductors,electromagnetic
interference shields,self-lubricated materials
Poly(lactic acid)/organo clay Improved properties
Polystyrene/organo clay Engineering plastics
656YANG,XU,AND GU
quenched to the desired isothermal crystallization temperature.The samples were maintained at the crystallization temperature for 40min during which the crystallization characteristics were recorded.Dur-ing nonisothermal crystallization experiments,sam-ples were heated at 50°C/min to 300°C,maintaining 300°C for 5min to eliminate the thermal and shear history effects,and then cooling at 20°C/min to 100°C.The peak corresponding to the maximum in the heat ?ow rate was taken as the crystallization temperature (T c ).
Melt nucleation and crystallization of PET and its nanocomposites were measured using a LEICA-DMLP polarizing light microscope (PLM)equipped with a Linkam-TMS94heating stage.The specimen was sandwiched between two glass slips,melted at 300°C for 5min to eliminate thermal history,cooled to 234°C for isothermal crystallization,and then main-tained there for 20min.
RESULTS AND DISCUSSION
Fundamental properties of PET nanocomposites The fundamental properties (intrinsic viscosity,car-boxylate end group concentration,lucency,color pa-rameter)of pure PET and PET nanocomposites are listed in Table II.The intrinsic viscosities of the sam-ples are approximately equal because the polymeriza-tions were controlled by melt viscosities.It can be found from Table II that the other parameters of PET/SiO 2nanocomposites are also consistent with those of pure PET,which means that the introduction of SiO 2nanoparticles had no signi?cant effect on the polymer-ization process.
Dispersion of nanoparticles in PET/SiO 2nanocomposites
It is well-known that the dispersion of nanoparticles in the polymer matrix has a signi?cant impact on
the
Figure 1TEM photographs of PET/2.0wt %SiO 2nano-composite prepared by in situ polymerization (a)?50,000(b)?100,000.
TABLE II
Fundamental Properties of Pure PET
and Its Nanocomposites
Specimen Intrinsic viscosity (dL/g)
O COOH (mol/103kg)
Lucency B Pure PET 0.6815.386.2 1.4PET/0.5wt %SiO 20.6814.886.5 1.6PET/1.0wt %SiO 20.6914.190.6 1.2PET/1.5wt %SiO 20.6814.585.3 1.1PET/2.0wt %SiO 20.6815.683.4 1.5PET/2.5wt %SiO 20.6816.082.2 1.1PET/3.0wt
%
SiO 2
0.69
13.4
88.6
1.3
PREPARATION AND CRYSTALLIZATION OF PET/SiO 2
657
properties of composites.21–24As the nanoparticles have a strong tendency to agglomerate,homogeneous dispersion of the nanoparticles in the polymer has been considered as a dif?cult process.A good disper-sion may be achieved by surface modi?cation of the nanoparticles under an appropriate processing condi-tion.25In this work,a novel approach has been utilized to disperse nanoparticles in the PET matrix.Figure 1shows TEM images of PET-based nanocomposite hav-ing 2.0wt %of SiO 2nanoparticles,where the dark areas represent the SiO 2particles and gray/white ar-eas represent the PET matrix.It is clearly seen that SiO 2nanoparticles have been dispersed fairly well.The sizes of SiO 2particles range between 10and 20nm.
Nonisothermal crystallization
A summary description of crystallization behavior of pure PET and its nanocomposites is shown in Table III.The temperature T c at which an exothermic peak occurs during DSC heating course (cold crystallization peak)and T *c during the cooling course (melt crystal-lization peak)were measured.
Comparison of the modi?ed samples with pure PET shows that the increase in melt-crystalline tempera-ture T *c with the increase of SiO 2content is obvious.The extent of increase in T *c is by about 28.5–44.9°C.The increase can be attributed to the incorporation of effective nucleation agent SiO 2and its satisfactory dis-persion in the PET matrix.It is well-known that the molecular chains of pure PET present higher in?exi-bility and less mobility.As a result,both crystalliza-tion rate and nucleation rate are very slow,corre-sponding to the low T *c .When SiO 2nanoparticles are added to the PET matrix,it enhances the crystalliza-tion rate of PET by providing large numbers of nucle-ation sites.In other words,SiO 2nanoparticles induce a growth of crystalline layer around their surface.The molecular chains can crystallize at high temperature and tend to transform perfectly at the same time.Both
crystallization rate and nucleation rate are very fast,corresponding to the high T *c .
Figure 2shows the DSC cooling scans of nonisother-mal crystallization from melt state for PET and its nanocomposites.The temperatures of peaks vary with the content of SiO 2over a range of 0–3.0wt %and their shapes become much narrower than that of pure PET.The effect of SiO 2nanoparticles on crystallization is reaching its maximum at approximately 2.5wt %whose crystallization peak is narrowest,but not at expectably 3.0wt %.As shown in Figure 2,the differ-ences in the onset and peak temperature of crystalli-zation curves between 2.5wt %and 3.0wt %SiO 2content nanocomposites are not very distinct.How-ever,the crystallization exotherm of PET/3.0wt %SiO 2is less narrow than that of PET/2.5wt %SiO 2mainly because of a queue in the crystallization curve at low temperatures.This may be due to a larger
TABLE III
Main Parameters of Nonisothermal Crystallization of All PET Samples
Specimen T g (°C)T c (°C)T *c (°C)T m (°C)H *c (J/g)(T *c
?T c )(°C)?T sc (°C)Pure PET 67.7135.0158.0242.929.023.084.9PET/0.5wt %SiO 268.9138.0186.5248.233.948.561.7PET/1.0wt %SiO 269.4138.1193.5248.033.055.454.5PET/1.5wt %SiO 269.7138.5195.8249.035.057.353.2PET/2.0wt %SiO 270.4137.2200.0249.033.562.849.0PET/2.5wt %SiO 270.8135.0202.9249.033.767.946.1PET/3.0wt
%SiO 2
71.0
130.0
202.7
251.0
34.8
72.7
48.3
T g ,the glass transition temperature;T c ,the cold-crystalline temperature;T *c
,the melt-crystalline temperature;T m ,the melting temperature;H *c
,the melt-crystalline heat;T *c ?T c ,the extent of crystalline temperature;?T sc ?(T m ?T *c ),the degree of
supercooling.
Figure 2DSC cooling scans of nonisothermal crystalliza-tion from melt state for pure PET and PET/SiO 2nanocom-posites.
658YANG,XU,AND GU
reduction in crystallization rate,probably caused by a larger crystal impingement arising from a higher number of growing spherulites.
From Table III,the cold-crystalline temperature T c of pure PET is about 135.0°C,in agreement with pre-vious reported data.26At a small addition of SiO 2nanoparticles,there is an obvious increase in T c ,while excessive SiO 2nanoparticles result in the decrease in T c .The maximum in T c can be observed in the PET/1.5wt %SiO 2nanocomposite.There may be two quite different ways in which SiO 2in?uences T c :(i)SiO 2nanoparticles act as balls,which can decrease interac-tivity between molecular chains of PET.This function of lubrication makes the molecular chains more ?exi-ble and mobile;(ii)the introduction of SiO 2nanopar-ticles with high surface activity produce an obstacle on the molecular chains movement,which will also re-duce the tendency for molecular chains to be crystal-lized,since they may react or chelate with functional groups (O COOH,O OH at the end,and O O O (CO))along the PET chains.This bridging function increases compatibility between the PET matrix and SiO 2nano-particles.At present,we still cannot verify whether both mechanisms operate concomitantly and which one dominates.
The change in T c and T *c might imply the in?uence of SiO 2on the crystallization of PET.The values of T *c ?T c in nanocomposites are obviously 25.5–49.7°C larger than those in pure PET.This implies that PET/SiO 2nanocomposites have excellent performance for injection molding.
In programmed cooling,the crystallization temper-ature re?ects the overall crystallization rate attributed to the combined effects of nucleation and growth.Thus,the degree of supercooling (?T sc ?T m ?T *c )may be used to measure the crystallizability of pure PET and its nanocomposites;that is,the smaller the ?T sc ,the higher the overall crystallization rate.The ?T sc values for the PET/SiO 2nanocomposites are smaller,by 23.2–38.8°C,than those of pure PET (84.9°C),and the PET/2.5wt %SiO 2exhibits the small-est ?T sc (46.1°C).The result again reveals that the overall crystallization rate for the PET/SiO 2nanocom-posites is higher than that of pure PET.
From these ?ndings,it can be concluded that SiO 2nanoparticles have a strong heterogeneous
nucleation
Figure 3Plots of isothermal crystallization for pure PET and PET/SiO 2nanocomposites (a)x (t )versus t of pure PET;(b)x (t )versus t of PET/1.0wt %SiO 2;(c)x (t )versus t of PET/2.0wt %SiO 2;(d)x (t )versus t of PET/3.0wt %SiO 2.
PREPARATION AND CRYSTALLIZATION OF PET/SiO 2
659
effect on PET,which offer enormous surface area and hence give rise to higher crystallization temperature and greater crystallization rate of PET during noniso-thermal crystallization.
Isothermal crystallization
To analyze the isothermal crystallization kinetic data of the PET nanocomposites,we adopt the well-known Avrami equation.27,28
x(t)?1?exp(?kt n)(1) where x(t)is the relative crystallinity,which is de?ned to be the volume fraction of polymer crystallized at time t.x(t)is derived by integrating the crystallization exotherm(H c)according to the DSC graph by the following equation:
x?t???
t dH c?t?
dt
?
t??dH c?t?
dt
dt
(2)
k is kinetic constant,and n is Avrami exponent, which depends on the mechanism of nucleation and the form of crystal growth.We can obtain a linear relation between log[-ln(1-x(t))]and log t by changing the form of eq.(1).
log[1?ln(1?x(t))]?log k?n log t(3) Figure3shows the plots of x(t)versus t for pure PET and its nanocomposites.Avrami exponent,kinetic constant calculated from isothermal crystallization are listed in Table IV.
On the basis of the classical crystal-nucleation the-ory,the nucleation is initiated by large-amplitude, localized?uctuations of some order parameter,such as density,leading to the appearance of small regions of the stable crystallizable phase.29–31When these re-gions are larger than some critical size,they will grow and eventually crystallize.However,the nature of such?uctuation has not been clari?ed.Phenomeno-logically,we can observe a transient time,the so-called induction period from amorphous state.In Table IV, the apparent increase in induction time(t ind)with the increase in the crystallization temperature may well be simply due to the slowing-down of the overall crys-tallization process(nucleation and growth).Patkar and Jabarin report that this behavior of t ind is due to the decrease in the nucleation rate at temperatures near melting point.32Kenny and Maffezzoli report that this delay is only representative of the induction time associated with the crystal nucleation.33The large
number of nuclei provided by the SiO2induces a large
amount of crystallites to grow simultaneously,over-
weighing the effect of high surface free energy.There
is a marked decrease in the induction time from0.50to
0.22min between the pure PET and PET/SiO2nano-
composites at200°C.
The Avrami exponent n depends on the mechanism
of the nucleation as well as the growth geometry,
which is usually an integer between1and4for dif-
ferent crystallization mechanisms.However,it has
also been observed that n is a fraction due to the
secondary crystallization or the crystal perfection.
Based on the results in Table IV,the Avrami exponent
n for constant SiO2concentration increases as a func-
tion of the temperature selected for crystallization.
The n of pure PET with a narrow spread in values
changes from2.72to2.20(with T iso?195–215°C), which are quite consistent with that reported by Chou
and Chang but lower than that reported by Hobbs and
Pratt.34,35For pure PET,its growth dimensions should
predominantly be a two-dimensional growth,accord-
ing to the de?nition of the Avrami exponent.36,37After
introduction of SiO2nanoparticles,the n values are
obviously higher than those of pure PET and are lo-
cated between3.45and2.24.For PET nanocomposites,
its growth dimension should be two-dimensional or
three-dimensional growth.This means that the addi-
tion of SiO2in?uences the mechanisms of growth of
PET crystallites.
TABLE IV
Parameters of the Isothermal Crystallization of Pure PET and PET/SiO2Nanocomposites
Specimen
T iso
(°C)
t ind
(min)
t1/2
(min)n
log k
(min?n) Pure PET
2150.6817.57 2.72?3.00
2100.6214.83 2.62?2.00
2050.567.80 2.60?1.70
2000.50 4.18 2.41?1.10
1950.48 3.03 2.20?0.80 PET/1.0wt%SiO2
2150.50 1.94 3.45?0.44
2100.48 1.44 3.200.12
2050.370.88 3.000.70
2000.350.68 2.60 1.06
1950.300.56 2.35 1.10 PET/2.0wt%SiO2
2150.45 1.47 3.00?0.11
2100.370.90 2.860.65
2050.300.64 2.62 1.11
2000.250.48 2.37 1.27
1950.200.38 2.35 1.65 PET/3.0wt%SiO2
2150.40 1.18 2.900.25
2100.320.77 2.560.82
2050.270.52 2.44 1.28
2000.220.45 2.33 1.44
1950.180.31 2.24 1.92 T iso,the isothermal crystallization temperature;t ind,the induction time of crystallization;t1/2,the half time of crys-tallization;n,the Avrami exponent;k,the kinetic constant.
660YANG,XU,AND GU
The kinetics constant k determines both the nucle-ation and the growth processes.From Table IV,it can be found that the k is extremely sensitive to crystalli-zation temperature,which decreases with increasing crystallization temperature.According to Supaphol,this is only valid when the crystallization temperature is within the range where nucleation mechanism is the rate-determining step.38,39At the same temperature,the kinetics constant k of modi?ed samples is about 78–1770times larger than that of pure PET,indicating that SiO 2is very effective as nucleation additive.
Table IV shows the effect of SiO 2nanoparticles con-tent on the half-time of PET crystallization (t 1/2)at different temperature.PET and PET/SiO 2nanocom-posites show a very noticeable linear decrease in t 1/2as the decrease of crystallization temperature,indicat-ing that the rate of crystallization is faster when the crystallization temperature is lower.This is consistent with the nucleation control of crystallization at high
temperature and re?ects that t 1/2is strongly depen-dent on composition and crystallization tempera-ture.40In contrast,Huang and Chang found t 1/2changed exponentially with decreasing crystallization temperature.41
Morphology of the PET spherulites
Figures 4and 5show the PLM images of isothermal crystallization for pure PET and its nanocomposite.The pure PET forms a normal spherulitic structure with a size of 5–10?m [Fig.4(a)],while the diameter of spherulites of the nanocomposite is as small as 1?m [Fig.5(a)]at the same crystallization temperature (234°C)and time (3min).As time goes on,the pure PET forms a larger spherulitic structure with a size of 15–20?m [Fig.4(b)].However,the change in the diameter of spherulites of the nanocomposite is very unconspicuous,even hard to distinguish [Fig.5(b)].
It
Figure 4Morphologies of PET crystallizing at 234°C (?400)(a)3min;(b)4
min.
Figure 5Morphologies of PET/1.0wt %SiO 2crystallizing at 234°C (?400)(a)3min;(b)4min.
PREPARATION AND CRYSTALLIZATION OF PET/SiO 2
661
is clear that the introduction of SiO2nanoparticles greatly affects the size of the PET spherulites.A great number of nucleus generated from SiO2simulta-neously grow in a limit space and lead to the forma-tion of small spherulites.
CONCLUSIONS
In this study,PET/SiO2nanocomposites were pre-pared by in situ polymerization.This method allows obtaining a homogeneous dispersion of the SiO2par-ticles.The addition of SiO2results in an increase in crystallization rate and in a reduction of the spherulite size and the surface free energy for nucleus formation. All the crystallization parameters(T c,T*c,n,k and t1/2) were found to be sensitive to the content of SiO2 within the explored range.The extent of increase in T*c is by about28.5–44.9°C.The crystallization kinetics constants of PET/SiO2nanocomposites are about78–1770times larger than those of the pure sample.With the addition of nucleating agent SiO2,smaller and more PET spherulites were observed.
References
1.Reinsch,V.E.;Rebendfeld,L.J Appl Polym Sci1994,52,649.
2.Gunter,B.;Zachmann,H.G.Polymer1983,24,1008.
3.Lu,X.F.;Hay,J.N.Polymer2001,42,9423.
4.Maiti,S.N.;Mahapatro,P.K.J Appl Polym Sci1991,42,310.
5.Maiti,P.;Okamoto,M.Macromol Mater Eng2003,288,440.
6.Linin,L.J Appl Polym Sci1999,71,1133.
7.Haubruge,H.G.;Jonas,A.M.;Legras,R.Macromolecules2004,
37,126.
8.Przygockiw,W.;Lochowicz,A.J Appl Polym Sci1995,19,2683.
9.Legras,R.;Dekonick,J.M.Polymer1986,27,109.
10.Zhu,P.P.;Ma,D.Z.Eur Polym J2000,36,2471.
11.Avella,M.;Errio,M.E.Appl Organomet Chem2001,15,435.
12.Alexandre,M.;Dubois,P.Mater Sci Eng2000,28,1.
13.Chang,J.H.;Kim,S.J.Polymer2004,45,919.14.Wu,Y.P.;Ma,Y.;Wang,P.Q.;Zhang,L.Q.Macromol Mater
Eng2004,289,890.
15.Taniguchi,A.;Cakmak,M.Polymer2004,45,6647.
16.Avella,M.;Errico,M.E.;Martuscelli,E.Nano Lett2001,1,213.
17.Hwang,S.H.;Paeng,S.W.;Kim,J.Y.;Huh,W.Polym Bull2003,
49,329.
18.Wang,D.;Zhu,J.;Yao,Q.;Wilkie,C.A.Chem Mater2002,14,
3837.
19.Lebaron,P.C.;Wang,Z.;Pinnavia,T.J.Appl Clay Sci1999,12,
11.
20.Davis,C.H.;Mathias,L.J.;Gilman,J.W.;Schiraldi,D.A.;
Schields,J.R.J Polym Sci Part B:Polym Phys2002,40,2661.
21.Kansy,J.;Consolati,G.;Dauwe,C.Phys Chem2000,58,427.
22.Petrovis,Z.S.;Javmi,L.;Waddon,A.;Banhegi,G.J Appl Polym
Sci2000,76,2272.
23.Rong,M.Z.;Zhang,M.Q.;Zheng,Y.X.;Zeng,X.M.Polymer
2001,42,3301.
24.Tang,Y.;Hu,Y.;Zhang,Z.;Wang,Z.Z.;Gui,Z.;Chen,Z.Y.;
Fan,W.C.Macromol Mater Eng2004,289,191.
25.Chan,C.M.;Wu,J.S.;Li,J.X.;Cheung,Y.K.Polymer2002,43,
2981.
26.Bian,J.;Ye,S.R.;Feng,L.X.J Polym Sci Part B:Polym Phys
2003,41,2135.
27.Avrami,M.J Chem Phys1939,7,1103.
28.Avrami,M.J Chem Phys1940,8,212.
29.Carmen,A.;Miren,L.;Jeanette,G.;Carmen,https://www.doczj.com/doc/858448701.html,pos Struct
2003,62,291.
30.Kelton,K.F.Solid State Physics;Academic Press:New York,
1991.
31.Imai,M.;Kaji,K.;Kanaya,T.;Sakai,Y.Phys B:Condens Matter
1995,213,718.
32.Patkar,M.;Jabarin,S.A.J Appl Polym Sci1993,471,749.
33.Kenny,J.M.;Maffezzoli,A.Polym Eng Sci1991,31,607.
34.Chou,R.M.;Chang,C.C.;Yu,T.L.;Tseng,Y.H.;Wu,M.J
Polym Int2001,50,213.
35.Hobbs,S.Y.;Pratt,C.F.Polymer1975,16,462.
36.Wunderlich,B.Macromolecular Physics;Academic Press:New
York,1976.
37.Sperling,L.H.Introduction to Physical Polymer Science;Wiley:
New York,1986.
38.Supaphol,P.Thermochim Acta2001,370,37.
39.Supaphol,P.;Spruiell,J.E.J Appl Polym Sci2000,75,337.
40.Mandelkern,L.Crystalling of Polymers;McGraw-Hill:New
York,1964.
41.Huang,J.M.;Chang,F.C.J Polym Sci Part B:Polym Phys2000,
38,934.
662YANG,XU,AND GU
雅思口语素材汇总之端午节 雅思口语素材:Dragon Boat Festival(端午节) Qu Yuan The Dragon Boat Festival, also called the Duanwu Festival, is celebrated on the fifth day of the fifth month according to the Chinese calendar. For thousands of years, the festival has been marked by eating zong zi (glutinous rice(糯米)wrapped to form a pyramid using bamboo or reed leaves) and racing dragon boats. The festival is best known for its dragon-boat races, especially in the southern provinces where there are many rivers and lakes. This regatta(赛舟会)commemorates the death of Qu Yuan , an honest minister who is said to have committed suicide by drowning himself in a river. Qu was a minister of the State of Chu situated in present-day Hunan and Hubei provinces, during the Warring States Period (475-221BC)(战国时期). He was upright, loyal and highly esteemed for his wise counsel that brought peace and prosperity to the state. However, when a dishonest and corrupt prince vilified Qu, he was disgraced and dismissed from office. Realizing that the country was now in the hands of evil and corrupt officials, Qu grabbed a large stone and leapt into the Miluo River on the fifth day of the fifth month. Nearby fishermen rushed over to try and save him but were unable to even recover his body. Thereafter, the state declined and was eventually conquered by the State of Qin. The people of Chu who mourned the death of Qu threw rice into the river to feed his ghost every year on the fifth day of the fifth month. But one year, the spirit of Qu appeared and told the mourners that a huge reptile(爬行动物)in the river had stolen the rice. The spirit then advised them to wrap the rice in silk and bind it with five different-colored threads before tossing it into the river. During the Duanwu Festival, a glutinous rice pudding called zong zi is eaten to symbolize the rice offerings to Qu. Ingredients such as beans, lotus seeds(莲子), chestnuts(栗子), pork fat and the golden yolk of a salted duck egg are often
全国翻译价格 关于全国各地区翻译价格我们根据客户的不同需求和具体情况，提供多种等级和特色的翻译服务，供客户选择：（注：以下报价均为参考价格，精确报价将根据稿件内容的难度、技术处理的复杂程度和时限要求的缓急而定。
品质控制 坚持高端定位是外语通翻译的核心要素，追求高品质翻译需要译员具备深厚的语言功底和专业背景知 识，更需要严格的质量控制体系来管理这一过程： 外语通六阶梯质量控制体系 第一阶梯：译文评估承接 分析稿件性质、用途要求、商务背景、专业术语、数量和交稿时间等，确定是否有100%的把握承接， 否则坚决放弃，以免因质量或交稿时间耽误客户和影响品牌形象。 第二阶梯：专业译员翻译 专业背景的译员只专注于一个行业领域的精准翻译，项目经理根据译文评估，从外语通全球译员库中 分析挑选多名此行业的专业译员成立项目组，统一专业术语和标准，协同翻译。 第三阶梯：翻译质量监控 项目经理监控翻译进展，每日集中疑难词汇，请签约专家释疑。每日抽查译文质量，及时解决译文质 量问题。 第四阶梯：译文校对排版 汇总所有译文，查错补漏，进一步统一术语，按原文进行排版，形成完整初稿。 第五阶梯：专家译审修改 专家译审对翻译初稿进行翻译准确性审核，确保译稿忠于原文，专业词汇纯正地道。 六阶梯：外籍母语润色第 在华外籍翻译（外译中稿件由中文功底深厚的编辑）对译稿的语法、词汇进行修正和润色，确保译稿 纯正、地道，达到母语品质。 外语通翻译严格执行《ISO译文质量体系》，《翻译质量国家标准GB/T 19682-2005》： 译文质量标准Ⅲ类通用笔译Ⅱ类专业笔译Ⅰ类高级笔译译文用途内容概要、参考资料一般文件和材料正式文件、法律文书、出版物错漏译率小于5‰小于2‰0‰ 译员经验3年以上5年以上8年以上 译员学历硕士以上硕士以上硕士以上 行业背景常识业内资深 海外背景无/短期中期长期 译文校对有有有 专家译审无有有 母语润色无无有 译文排版简单排版详细排版出版级别
口语常用背诵素材 一，喜好和厌恶： 1.（释放压力）I guess most young people enjoy listening to music. It’s a perfect way to reduce stress/relieve stress. (*It’s a perfect stress-buster.) 2.（休闲）I think the best way to relax and kill time (kick back and relax) is to be with friends. Chatting with them helps me unwind/wind down (* Chatting with them is very therapeutic). 3.（放松）I found it pretty relaxing to flick through a magazine before going to bed (*before hitting the sack/hitting the hay). 4.（运动）Jogging on sunny days and simply basking in the sun(bathing in the sun) is super enjoyable(pleasurable). /Jogging is my favorite workout. It can always cheer me up after I’ve been down and depressed. And it can help me shed some unwanted weight. 5.（喜欢，提升心情）I’m quite into watching sitcom (I’m fascinated by, I’m crazy about, I adore, I’m very fond of...). Spending 20 minutes in front of the screen and having a good laugh after dinner really puts me in a better mood/ switch my mood/ lift my spirits. 6.（天气）I fancy spring most compared to the other three. Summer is simply too hot and stuffy (*muggy), and you can’t stay out for two minutes without getting sweaty and smelly. Autumn is too dry and winter too freezing cold. 7.（电影）I’m a movie buff (Movies are my biggest pastime), and I would either catch one on my couch or go to the movie theatre when they have the one I like on the big screen./ It's a great form of relaxation for me to while away the hours of a long flight, to keep my family together on the sofa, and to give me a bit of a thrill. 8.（无聊困难）I’m terrible at what I study now./(History is never my forte/ my strong suit). The classes are kind of a drag (It’s super dull/ *It’s mind-numbing), and there’s always loads of (tons of) homework to do. Memorizing those facts and years is a lot of effort (is tricky; is no picnic; is challenging for me). 9.（不能忍）I can’t stand (I hate, I totally dislike) the busy traffic in my city. I’m sick and tired of always getting stuck in traffic for a long time during rush hours. It really bothers me (It drives me crazy, *It drives me up the wall). 10. （受欢迎）Hip-hop is really trendy (is catching on, is all the rage) among young people these days. 二，时间和地点 11. （优点）What’s great about my home town is that there are plenty of shopping malls, coz I’m a shopaholic and I can shop for hours. 12. （远）The stadium is quite far away from where I live, and every time I want to do there, it takes me roughly 40 minutes by bus to arrive. (It’s one-hour drive from the city center.) 13. （方便）My apartment is in the center/heart of the city, a handy location where I can find supermarkets and clubs right on my doorstep. It’s a bit noisy though. 14. （近）I’m a movie-goer and and there’s a movie theater pretty close to my home, so I go there quite often (frequently). (close to my home= *within walking distance of my home , *in close proximity to my home) 15. （经常）I have a heavy workload at school, so I have to go to the library to study pretty much
雅思口语素材 Document serial number【LGGKGB-LGG98YT-LGGT8CB-LGUT-
Useful Expressions: Words and phrases Friends and communication: solidify/ strengthen/ enhance/ promote communication / connection with mutual understanding relationship network/circle of f r i e n d s cultivate/develop friendship with s b . keep steady relationship with sb. establish interpersonal networksac build up the social circle spur message transmission Knowledge and experience widen one’s outlook broaden one’s vision/horizon acquire knowledge and skills comprehensive/overall quality
expand/enlarge one’s scope of knowledge knowledge reserve/base/storage theoretical knowledge practical skills social experience broaden one’s knowledge base promote one’s overall/ comprehensive competence accumulate experiences learn lessons from past experiences Work and experience the scarcity of employment o p p o r t u n i t i lay the foundations for career p r o s p e r i t y
U s e f u l E x p r e s s i o n s: Words and phrases Friends and communication: mutual understanding solidify/ strengthen/ enhance/ promote communication / connection with relationship network/circle of friends cultivate/develop friendship with sb. keep steady relationship with sb. establish interpersonal networksac build up the social circle spur message transmission Knowledge and experience widen one’s outlook broaden one’s vision/horizon acquire knowledge and skills comprehensive/overall quality expand/enlarge one’s scope of knowledge knowledge reserve/base/storage theoretical knowledge practical skills social experience broaden one’s knowledge base promote one’s overall/ comprehensive accumulate experiences competence learn lessons from past experiences Work and experience the scarcity of employment opportunities lay the foundations for career prosperity immerse oneself in endless job tasks boost/augment/enhance efficiency be adept in boost one’s c ompetitiveness Health and pressure diminish individuals' leisure time drive away lassitude lighten one’s burden homework/workforce overload
翻译公司收费标准 1.客户需要翻译的目标语言的普遍性和稀缺性可能导致非常 不同的费用。英语比较普遍，需求大，市场专业的英语翻译人 才也很多，翻译公司无论是从降价到抢占市场，还是成本核算 来考虑，英语收费都比较合理和透明。 其他诸如法语、德语、日语、俄语排在第二梯队，翻译公司收 费标准一般都是200-280元，视稿件专业度和数量略有调整； 意大利，西班牙，越南，泰文等东南亚语种已经接近稀有语 种了，翻译报价至少300元千字起。 2.根据翻译项目类型 常见的翻译方法主要包括翻译翻译、同声传译、本地翻译、口译翻译等，翻译项目自然是不同的收费。 3.根据翻译项目时长 这一时期的持续时间主要是指项目长度：同声传译、会议翻译、商务洽谈、双语主持人、口译、护送翻译、展览翻译，当然，视频翻译、音频翻译按时间计算的时间和会议类型是一个重要因素，是翻译时间决定翻译价格的一个重要因素。 4.根据翻译项目字数
翻译项目的字数是影响收费的重要因素之一，翻译字数主要对于笔译而言，例如：文件翻译、图书翻译、资料翻译、画册翻译等等，这些文件资料的字数决定了项目的翻译价格和翻译收费标准。 5.根据翻译项目语种 主流语种：英语、日语、韩语等和小语种：阿拉伯语、希腊语、印尼语等的翻译收费标准区别。我们知道：“物以稀为贵，”所以小语种的翻译报价会比主流语种收费要高的。 6.根据翻译项目难易程度 对于翻译公司来说，翻译费在很大程度上取决于翻译的难度程度，不同的行业术语不同，难度不同; 专业翻译公司将根据翻译人员的翻译水平、专业知识、翻译经验等方式来评价自己的翻译团队，高层次的翻译人员当然都是高收费; 如通用翻译、精细翻译、出版层次等不同类型的翻译报价不同，稿件的行业领域、材料难度、选择翻译类型等都是决定翻译公司收费标准的因素。
近期雅思口语卡片新题素材汇总 人物Describe a classmate of yours Describe a good friend Describe a happy person Describe a colleague Describe a neighbor Describe your own personality Describe a family member Describe a child you know Describe an old person Describe an old person who has influenced you the most Describe a successful person Describe a singer Describe a sportsman Describe a movie star Describe a character in TV or movie Describe a teacher of yours Describe a famous person that you want to spend a day with.地点Describe a building at schools Describe a historical place
Describe a monument Describe an interesting building Describe a lake, river or sea. Describe a peaceful place Describe a leisure place Describe a park Describe a place of interest Describe a natural beauty Describe a city you want to live in Describe a place you have visited Describe a place you always go for shopping
英文合同翻译价格英文合同翻译需要多少钱 在企业的经营过程中，有时候可能会涉及到翻译这个问题，但是一般的小企业并没有专门的人去做这件事情，大部分都是外包。那么对于企业来讲，翻译一份英文合同需要多少钱呢？作为浙江省最大的翻译公司，以琳翻译就在这里为大家解读一下。 一般来讲，翻译这项服务都是以字数来计价的，市场上的一般的价格是50-80元/千字，这是一个基本的价格。但是不同的公司的专业性质不一样的话，所给出的价格也是不一样的。对于公司的衡量标准来讲，影响价格的因素主要有：公司的资历、翻译人员的专业性、翻译文件的种类、难度等。所以，如果你需要去找翻译公司去服务，那么就需要考虑这些方面的东西。而对于合同这种文件，对于公司来讲是十分重要的，所以也需要去找专业的公司去进行翻译，如果是找一个资质不够的公司或者团队，那么就可能产生一些意想不到的问题，从而影响到公司的最终利益。 下面，我们来看看以琳翻译给出的翻译的价格。 从上面的价格可以看出，以琳翻译给出的价格是高于一般市场上的价格的，最低级别的翻译是160元/千字，然后分为A、B、C三级。C级译稿为普通中籍译员+中籍译员审核，满足客户对译文的普通要求。这是对于一般的合同而言的，但是如果是部分专业性质较强或者要求比较高的译文的话，那么可以选择更高级别的翻译，当然价格还是相对比较高的。 那么以琳翻译的资质是怎么样呢？我们再来看一下。 杭州以琳翻译有限公司是浙江省最大的实体翻译公司、中国翻译协会单位会员、美国翻译协会会员、全国翻译专业硕士研究生教育实习基地、西博会指定合作伙伴、以琳杭州翻译公司翻译团队成员均具有五年以上专业翻译、项目管理经验，绝大部分成员具有十年以上行业翻译经验。翻译服务涵盖英语、法语、韩语、日语、德语、俄语、西班牙语、葡萄牙语、
一.雅思P2相关话题 一日假期 和外国朋友一起吃饺子的建议 1.The best way to eat a dumpling is in one bite. “Dumplings are designed to be consumed in one mouthful, as it’s the best way to enjoy the combination of the meat filling and the very thin and springy flour wrapper,” If you can’t use chopsticks, eat your dumplings with your fingers. Avoid using a fork at all costs, as piercing the dumpling will compromise the flavour. 3.Mix two parts vinegar with one part soy sauce for the perfect dumpling sauce. Add young ginger slices too， Chili oil is also a great addition when available. 4.Dumplings are just one element of dim sum. “Dim sum doesn’t just include dumplings. It’s also braised dishes like pork ribs, chicken feet, and beef balls. It’s actually small tapas-style dishes that are eaten in Cantonese restaurants at lunchtime,” 5.Xiao long bao dumplings are different from others as they contain broth. They originated in the Jiangnan region of China and are prepared in bamboo steaming baskets called xiao long, hence the name. 6.When eating xiao long bao or a dumpling with a ~soupy~ interior, opt for chopsticks and a spoon. “As soon as the dumplings arrive at your table, lift one from the steamer basket onto a soup spoon. Next, tear the skin of the dumpling by pressing the chopsticks from the side of the dumpling onto the spoon. The broth will ooze out onto the spoon. Sip the soup then enjoy the dumpling in one mouthful.” 7.You can tell whether your dumpling was cooked fresh or frozen by looking at the skin. “The skin of a freshly made dumpling is springy and light. “Frozen ones tend to be soggy.” 8.When makingdumplingsat home, try to keep your packages small.
精诚英语翻译报价50-80元千字（市场价格100左右 精诚英语翻译工作室是由众多英语方面精英组成的翻译团队,一直致力于为广大中小企业和个人提供专业低价中英文翻译服务。价格是我们永远的优势！！！！最低价格支付宝担保交易，让你省钱又放心接受试译！！自信源于专业可以百度搜索精诚英语翻译找到我们 选择我们的理由：可以百度搜索精诚英语翻译找到我们 1.保证价格最低，团队网络化运作，无需经营成本，可以通过低价让利于客户。（有些客户看到这么低的价格还不敢相信，但是对于我们来说是完全可以接受的。） 2.保证准时、保密、准确 3.接受淘宝交易，让您没有任何担忧。 4.长期翻译经验，保证质量让您满意。 龚如心遗产案虽然告一段落，「遗产」二字仍然成为近日香港的焦点。新春期间，民政事务局局长曾德成表示，政府将展开全港非物质文化遗产首期普查，希望市民为遗产清单提出建议。 「遗产」是「资产」？ 近五、六年间，香港对保护本地小区和文化传统的意识高涨，现在政府带头要列一个「非物质文化遗产」清单，理应是很受欢迎之举。不过普查尚未展开，就引来学者争议，其中单是「非物质文化遗产」这个译名，就引起不少误会。 「非物质文化遗产」的原文是intangible cultural heritage（英文）或patrimoine culturel immateriel （法文），是联合国在1997年以尊重多元文化为大原则而提出的概念，并由联合国教科文组织制定「保护非物质文化遗产公约」，2006年生效。 「非物质文化遗产」是中国大陆的翻译，香港有学者不约而同就「非物质」和「遗产」二字提出质疑。香港城市大学中国文化中心主任郑培凯早在2005年就大声疾呼译名不妥。他认为原文heritage/patrimoine的意义是「传承」而非资产，不容易引发出财产的概念。而现在约定俗成译作「遗产」，容易令人觉得祖宗留下的东西，是可以变卖和投资的生财工具，与联合国提出的文化传承精神背道而驰。郑教授认识，正确的译名是「非物质文化承继」或「非实物文化传承」。另一位民俗学研究者陈云进一步指出，intangible「乃触摸不到的事，无形无相之事」，应用「精神价值」代之，「非物质」有消灭了精神之嫌，所以中国人应堂堂正正将之翻译为「无形文化传承」。 姗姗来迟的「遗产」 不论是「非物质」还是「无形」，「遗产」还是「承传」，即使公约成员国中国曲译甚至错译，香港特区政府还是只能照单全收。而且，随之而来的不止是字面的斟酌，而是「遗产」的搜寻和管理问题。 中国自2005年起，就开始非物质文化遗产（由于这个名称已约定俗成，故下文仍沿用之，并简称为「非遗」）普查，并陆续列出清单。香港也在翌年提出编制非遗清单，但却延至去年才聘专家普查，估计最快要2012年才完成。 非遗普查尚未展开，在国家文化部的再三邀请（或是说催促？）下，去年九月，香港终于申请将长洲太平清醮、大澳端午游涌、大坑舞火龙和香港潮人盂兰胜会列为第三批国家级非遗，预计今年六月有结果。 其实香港已错过了2006和2008年首批和第二批的申报机会，所以，至目前为止，在中国的文化版图上，香港是唯一没有任何有形和无形「遗产」的主要城市／特区，就连比邻的澳门也凭神像雕刻工艺获得2008年国家级非遗之「奖项」。 有人说非遗不过是人有我有，纯粹锦上添花；也有人说，中国在维护主权和领土完整的概念下，又怎能在文化层面少了香港一席？香港能够「出产」一个非遗，中国在全球的文化图谱中就多一个筹码。 姑勿论背后原因为何，由于「保护非物质文化遗产公约」也适用于香港，香港特区政府就有责任找出和保护濒危失传、与社会关系密切及具香港独特性的文化传统。现在起步虽迟，但为时未晚。 「遗产」的管理问题 不过，既然政府要展开普查，另一个问题来了。民间传统应该是属于民间的，并由民间自行发展，还是属于官方，由政府承担保护与管理？ 据政府委聘负责首期普查的香港科技大学华南研究中心主任廖迪生表示，政府至今仍未有任何政策配合或承诺给予全面的保护，所以，即使清单出炉，有些遗产仍有可能难逃「破产」的命运。他强调制作非遗清单只是第一步，更重要的是如何保护这些项目。 再问民政事务局，曾德成局长除了曾向立法会议员表示，制定清单是向国家文化部申请列为国家级非遗的第一步，进而再向联合国教科文组织提出申报为世界非物质文化遗产，他所提出的，就是以遗产作招徕吸引外地游客，「以提升香港作为旅游目的地的吸引力」。 这才是令人担心的地方。「非遗」这个金漆招牌在中国许多地方都有点石成金之效。戴上这个冠冕，民俗文化很容易沦为生财工具、游客的消费品，连婚嫁仪式也可用来表演，完全违背了保护非遗的原意。曾德成之言，是否意味着香港也要跟着祖国一起走上同一条路？
雅思口语素材训练 by Tina Li Do you like music??A—肯定:Definitely yes, everyone enjoys music, and I am no exception! I love... 否定 :Well, honestly speaking, music is really not my cup of tea, simply because... ( 给出直接原因) What—pop, techno ( 电音音乐), hip-hop, rock, meditation ( 冥想乐) and especially light music.( 罗列名词) Where—Normally speaking, I would like to listen to music with my earphones when I take a ride on public transportation. ( 给出一个具体的场景) When—As long as I couldn’t go to sleep, I’d like to listen to some light music to calm myself down. ( 给出一个条件 :As long as I..., I would...)
Who—My most favourite singers include Adele, James Blunt, Avril Lavigne, and so forth. ( 喜欢的歌手) Why—I am fond of music mainly because it can cheer me up greatly when I feel down/low/ blue/bored/tired/depressed. ( 心情不好的时候让我高兴起来)?Besides, I also believe that music is an indispensable part of culture and tradition, through which I could have a better understanding of different cultures around the world, including cowboy culture, African-American street culture, the three main reli- gions and so on. ( 有助于理解不同的文化) Do you like watching movies?? A—Speaking of movies, yes, I am a big fan of all types of movies, such as...?What—comedy, action, romance, sci-fi, manga, vampire, zombie, animation...
英文翻译价格 根据以英文作为母语的人数计算，英文是最多国家使用的官方语言，英语也是世界上最广泛的第二语言，也是欧盟，最多国际组织和英联邦国家的官方语言之一。但仅拥有世界第二位的母语使用者，少于标准汉语。上两个世纪英国和美国在文化、经济、军事、政治和科学上的领先地位使得英语成为一种国际语言。如今，许多国际场合都使用英语做为沟通媒介。英语也是与电脑联系最密切的语言，大多数编程语言都与英语有联系，而且随着网络的使用，使英文的使用更普及。英语是联合国的工作语言之一。 为了方便大家了解英文翻译价格，小编在目前汇集最多翻译团队的高校译云上面获得了不同翻译精英团队所展示的价格。 暨南大学翻译中心：中英---普稿---150---千字英中---普稿---250---千字 武汉理工大学-外国语学院MTI翻译中心 ：中英互译中英130-150 英中100-130 华中科技大学-翻译研究中心 ：中英互译中英120-150 英中100-120 湖南科技大学MTI中心：中英---普稿---150---千字 上海师大外国语学院翻译中心： 中英---普稿---200元---千字英语普通文本译成汉语---120元---千字西南大学翻译中心：中英---普稿----300---千字英中---普稿---200---千字 上海理工大学MTI翻译中心：中英---普稿---100---千字 南京财经大学外国语学院翻译研究中心：中英---普稿---100---千字 一般英文翻译价格是是在100—300元每千字，根据译员质量、翻译内容、需要的时间等都会有一定的波动，所以以上价格供大家参考，具体的可以准备好稿件了去问，这样会更加准确一些。
做有偿工作的人 Describe a person you know who is doing a paid job. You should say: Who this person is What job it is; How long the job lasted; And explain why you or this person chose to do this job. 让你笑的小孩 Describe a time that a child did something that made you laugh. You should say: When this happened Who the child was What the child did And explain why it was funny 特殊的旅行 Describe an educational trip you went on when you were in school. You should say: When and where you went; Who you went with; What you did; And explain what you learned on this trip.
Describe an electronic machine you want to buy. You should say: What it is When you know this machine What specific And explain why you want this machine 难忘的广告 Describe an unforgettable advertisement (that you saw or heard liked) You should say: Where you saw or heard it What kind of advertisement it was What the contents of the advertisement were (or, what product or service was advertised) And explain how you felt when you saw or heard this advertisement/why you like it
【2019-2020】雅思口语话题素材-精选word文档 本文部分内容来自网络整理，本司不为其真实性负责，如有异议或侵权请及时联系，本司将立即删除！ == 本文为word格式，下载后可方便编辑和修改！ == 雅思口语话题素材 雅思口语素材总结雅思口语要求学生平时多多的积累素材，在口语方面要不断的加强练习。烤鸭们要多模拟不同的场景，多用丰富的口语短语，这 样你的雅思口语水平才能越来越高。下面是常用的一些口语短语，供大家参考！ 1、 a change of pace 改变步调;换口味 You cant do these chemistry experiments all day long . You certainly need a change of pace . 2、 a far cry from 相距甚远 The published book is a far cry from the early manuscript . 3、 and how 的确 A ： Shes a good dancer . B ： And how . 4、 a matter of time 时间问题 It is only a matter of time . 5、 a phone call away 一个电话之远，即愿意过来帮忙 If you need my help , do let me know . Just remember I am a phone call away . 6、 a while back 不久以前 Well , I listened to that CD you lent me a while back . 7、 all along 一直 I knew it all along . 8、 anything but 绝对不 I was anything but happy about going . 9、 account for 解释 How do you account for it ? 10、 after all 毕竟;终究 A ： Ive just seen the X - rays and your teeth look just fine . B ： I see . Then there is nothing to worry about after all . 11、allergic to 对过敏 Oh man ! Something in this room is making my eyes itch . I must be allergic to something . 12、 at sbs service 愿为某人服务 I am at your service at any time . 13、 around the clock 24小时不停 Martha studied around the clock for management exam . 14、 as far as I know 就我所知 But as far as I know , he once won the world champion at the Olympic Games . 15、 at home with 对很熟悉 She is at home with problems like this . 16、 back out 退出 A ： Wasnt Bert supposed to sing tonight ? B ： Yes , but he backed out at last minute . 17、be cut out for 适合于，有做某事物的天赋 She is cut out for a dancer . 18、 be absorbed in 全神贯注于某事物 She has been absorbed in a horrorfiction . I cant tear her away . 19、 be addicted to 对某事物上瘾 She has been addicted to drugs for years . 20、 be attached to 对某事物有感情 A ： Im amazed that you are still driving that old car of yours . I thought you would have gotten rid of it years ago . B ： It runs well and Ive actually been quite attached to it .