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Aqueous phase Ag nanoparticles with controlled shapes fabricated by a modified

Aqueous phase Ag nanoparticles with controlled shapes fabricated by a modified
Aqueous phase Ag nanoparticles with controlled shapes fabricated by a modified

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Applied Surface Science xxx (2010) xxx–xxx

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Applied Surface

Science

j o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /a p s u s

c

Aqueous phase Ag nanoparticles with controlled shapes fabricated by a modi?ed nanosphere lithography and their optical properties

Yujun Song a ,b ,?,Hani E.Esayled-Ali b

a Key Laboratory of Aerospace Materials and Performance (Ministry of Education),School of Materials Science and Engineering,Beihang University,Beijing 100191,China b

Applied Research Center and Department of Electrical and Computer Engineering,Old Dominion University,Newport News,VA 23602,USA

a r t i c l e i n f o Article history:

Received 4November 2009

Received in revised form 15March 2010Accepted 20March 2010Available online xxx Keywords:Nanoparticles Silver

Fabrication Aqueous

Nanosphere lithography Surface plasmon resonance

a b s t r a c t

We have developed a modi?ed nanosphere lithography (NSL)process to fabricate surface-con?ned Ag nanoparticles (NPs)with controlled shapes.NPs with different shapes,such as triangular,quadrilateral,pentagon or trapezoidal with rounded tips or edges,can be fabricated by this process.These Ag NPs can be dislodged into water forming NPs in an aqueous environment.The developed process results in better NP shape retaining than those obtained using the routine NSL process.The UV–vis absorption of the surface-con?ned Ag NPs show distinct blue shift and reduced intensity after surface modi?cation.The NPs produced by the modi?ed NSL and dislodged in water have signi?cantly less density of debris as observed by transmission electron microscopy and UV–vis absorption spectrum.

? 2010 Elsevier B.V. All rights reserved.

1.Introduction

Noble metal nanoparticles (NPs)exhibit selective absorption and scattering at particular light wavelengths in the visible range due to their localized surface plasmon resonance (LSPR)[1,2].The light scattering from NPs is strong enough to be directly observed by a charge coupled device (CCD)camera,a color digital camera,or visually using an optical microscope [3].Unlike ?uorescent probes and quantum dots,noble metal NPs do not photo-decompose and their optical properties are preserved after being functional-ized by biomolecules [4,5].The plasmonic couplings among noble metal NPs have shown that they can be used as reliable molecule rulers with a higher time resolution,longer life time,and longer detection distance than dye-based ?uorescent resonance energy transfer (FRET)based techniques [4,6].For these reasons,their unique optical plasmonic properties make them of much interest as optical nanoprobes and plasmonic nano-rulers.This can allow for long-term in situ quantitative analysis of the dynamic and kinetic parameters of biological processes with resolution down to the sin-gle molecular (SM)level and on the nanometer scale [5].In addition,since LSPR can con?ne and carry light of different wavelengths on the surface of NPs,LSPR nanoparticle devices can overcome the light

?Corresponding author.

E-mail addresses:songyj@https://www.wendangku.net/doc/3318789880.html, (Y.Song),helsayed@https://www.wendangku.net/doc/3318789880.html, (H.E.Esayled-Ali).

diffraction limit and,thus,have vast applications in optical circuits and sensors [7].

The chemical and physical properties (e.g.magnetic,catalytic or optical)of NPs are dependent on their sizes,shapes and spatial arrangements [3,8–13].Recent investigations have demonstrated that the optical properties of noble metal NPs signi?cantly depend both on their shapes and sizes [3,9,14].Therefore,the ability to reproducibly control the shape of the fabricated NPs is of much interest.Chemical synthesis of noble metal NPs relies on the abil-ity to reduce a metal salt in a controlled environment [15].An alternative to solution phase nanoparticle (NP)fabrication is to fabricate NPs on solid substrates and then release them into a solu-tion.Recent progress in nanosphere lithography (NSL)has shown that this method provides a good template for shape-controlled fabrication of surface-con?ned NPs.This also allows for ?exi-ble functionalization on the clean surface [16].Van Duyne and co-workers have developed this process and used it to fabricate solution phase NPs in ethanol [15].However,their results indicated that most of the NPs in the solution have nonuniform surface mor-phologies with truncated tips in addition to the presence of debris and some of the NPs attached together on the glass substrate sur-face causing the agglomeration of the released NPs.In addition,aqueous phase NPs are expected to be more biocompatible than those in ethanol.

We present a modi?ed NSL process to fabricate Ag NPs with con-trolled shapes on glass substrates.These modi?cations were made by thermal annealing of the triangular nanoprisms,sonication to

0169-4332/$–see front matter ? 2010 Elsevier B.V. All rights reserved.doi:10.1016/j.apsusc.2010.03.102

2Y.Song,H.E.Esayled-Ali/Applied Surface Science xxx (2010) xxx–xxx

remove weak tips,slight etching of the glass substrates under the NPs,removing debris and small broken parts around the NPs on the substrates.Thiol compounds were adsorbed on the NPs prior to dislodging them into water.These aqueous phase NPs show much more uniform shapes than those obtained by the traditional NSL process and give a narrower UV–vis absorption peak.

2.Materials and methods

2.1.Chemicals and supplies

Polystyrene nanospheres with diameters of290nm were purchased from Duke Scienti?c Corporation,with concentra-tion of1.0–4.0wt.%and uniformity of coef?cient of variability (C.V.%)<5.0%.Other supplies used were Ag wires(99.999%) and Cr shots(99.99%)from Alpha Aesar,borosilicate glass substrates(No.2,?25mm)from SPI.1-Octanethiol(1-OT),11-mercaptoundecanoic acid(MUA),1,6-hexanedithiol(1,6-HDT), 6-mercapto-1-hexanol(6-MCH)from Sigma–Aldrich Chem.Inc.,1-butanethiol(1-BT),Tiopronin(TP),ethanol,tetrahydrofuran,nitric acid,sulfuric acid,hydrogen peroxide(30%),ammonia(37%),HF acid(48%)and hydrochloride acid(37%)from Beijing Chemical Reagents Inc.All chemicals were used without further puri?cation.

2.2.Fabrication of Ag nanoparticles by a modi?ed nanosphere lithography process

Nanosphere lithography can be used to fabricate clean NPs that are grown on a glass substrate.A monolayer colloidal polystyrene nanosphere mask was prepared by drop coating of~3.0–4.0?L, 3–10times diluted nanosphere solution onto the glass support and leaving them to dry overnight.The procedure to fabricate the nanosphere mask is as follows.The glass substrates are cleaned by sonication with a mixture of sulfuric acid and hydrogen peroxide (3:1=conc.H2SO4:30%H2O2,volume ratio)at80?C for30min and washed using suf?cient nanopure water.Then,the glass substrates are sonicated in a mixture of ammonia and hydrogen perox-ide(5:1:1=H2O:NH4OH:30%H2O2,volume ratio)to increase the hydrophilic property on the surface of the glass substrates.Finally, the glass substrates are washed using suf?cient nanopure water again and stored in the nanopure water for future use.When drop coating is to be performed,the glass substrate is picked up from the nanopure water from one of its edges.The remaining water droplets on the glass substrate are removed by touching the oppo-site edge on?lter paper.The substrate is then left?at in a clean Petri-dish with a tilt angle of~3–5?.A15?L of PS nanosphere solu-tion is added on the surface of the glass substrate using a droplet. The water spreads over the whole glass substrate to form a semi-ellipsoidal shaped water spot.The Petri-dish is left for enough time to allow the water to evaporate.During evaporation,the tempera-ture is kept at18±3?C and the humidity is kept~50±5%.

The dry nanosphere mask was mounted inside an electron beam evaporation deposition system.A calibrated quartz crystal microbalance was used to measure the thickness of the Ag?lm deposited on the nanosphere mask.Following Ag deposition,the nanospheres were released by immersing the glass cover slip into a CH2Cl2solution for1–10min,followed by washing in ethanol and then sonication for3–5s,washing by tetrahydrofuran,washing by nanopure water,and?nally drying in inert gas?ow.This routine process results in well-de?ned periodic nanoprisms with thin and weak tips and edges.These NPs produce broken parts and irreg-ular morphologies upon releasing into a solution.Therefore,three modi?cations of the standard procedure of NSL were made in order to obtain stable NPs with different shapes.These modi?cation to the process are:(1)Releasing the nanospheres by immersing the cover slip into a5%HCl solution for30min,immersing the glass substrates into CH2Cl2for30s,then sonication in ultrasonic bath (500W)for~20–60s.(2)Annealing the fabricated Ag nanoprisms on the glass substrates at100–300?C for2–5h,then cleaned by immersing the glass cover slip into5%HNO3for10–20s to remove any surface contamination and dissolve debris around the NPs,and then washing by large amount of nanopure water.(3)Immers-ing the glass substrates into5–10wt.%HF and HCl acid mixture (1:1=HF:HCl)for30–60s or10%NaOH solution for60–120s to etch part of the glass substrate under the Ag NPs,and then washing the substrates with suf?cient nanopure water.The?nal step was to wash the glass substrates with the Ag NPs,dry them by inert gas ?ow,then placing them in a desiccator.

2.3.Surface modi?cation of Ag nanoparticles

The surface of Ag NPs can be modi?ed by chemicals contain-ing thiol groups(such as1-OT,1-BT,MUA,TP,1,6-HDT,and 6-MCH)forming strong sulfur–silver covalent bonds.We used1-OT and MUA as functional reagents.The functional solution was prepared by dissolving0.049g1-OT and0.073g MUA into100mL pure ethanol in a100mL volume?ask to form2mM5:11-OT/11-MUA solution.The Ag NPs were once again cleaned by5%nitric acid and then immersed into the2mM5:11-OT/11-MUA solution overnight.

2.4.Releasing of surface modi?ed Ag nanoparticles into water

The releasing aqueous solution contained5vol%of2mM5:11-OT/11-MUA in nanopure water.The glass substrates with surface modi?ed Ag NPs were picked up from the functional solution and immersed into the releasing solution.The NPs were then sonicated for30–120s to remove them out of the substrates into the releas-ing solution.For a2–4mL releasing solution,4–8glass substrates were used in order to reach a NP concentration suitable for optical property measurement.

2.5.Characterization of nanosphere templates and Ag nanoparticles

Atomic force microscopy(AFM)images of the monolayer of nanosphere templates and Ag NPs were collected using the tap-ping mode.Etched Si nanoprobe tips(radius<10nm and cone angle 20?)were used with resonance frequencies between280kHz and 320kHz.All images were scanned in ambient conditions.

The sizes and shapes of aqueous phase Ag NPs were character-ized by transmission electron microscopy(TEM).A7?L NP solution was pipetted onto400mesh copper TEM grid.After precipitation for30–45min,the excess NP solution was carefully removed with ?lter paper.Then,the TEM grid was dried overnight.The nanopar-ticle size distribution and shape were determined by TEM(JOEL 2100F or CX100).For the anisotropic Ag NPs with sharp tips,the size of the prism-shaped NPs was determined by averaging the length of the three edges;the size for triangle NPs with rounded tips was based on the length between rounded tips;the size of the circular-shaped NPs was based on their diameters;and the size of the quadrilateral or pentagon-shaped NPs was based on their edge lengths;while the sizes for other shapes were determined by their mean diagonal lengths for about45–110NPs.

An UV–vis spectrometer(GBC Cintra-20,Australia)was used to record the UV–vis absorption spectra of the Ag NPs on the glass substrates and those released into the aqueous solution.X-ray pho-toelectron spectroscopy(XPS,ESCALAB250,VG Scienti?c)was used to con?rm that the thiols were conjugated on the surface of the Ag NPs.

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Fig.1.Nanosphere templates based on290nm spherical polystyrene nanospheres for Ag nanoparticle fabrication.

3.Results and discussion

The initial critical step in NSL is formation of a near-uniform large-scale nanosphere template.We found that drop coating pro-duces more uniform templates than spin-coating or dip-coating. The uniformity of the nanosphere template produced by drop coating depends on the nanosphere type and concentration, the hydrophilic properties of the substrate,the environmental humidity and temperature,and the drying speed.A near-uniform monolayer nanosphere template can be prepared on almost the whole glass substrate(25mm diameter).Fig.1shows one typi-cal area of a near-uniform monolayer template over scale~20?m. From the magni?ed image,a selected area shown in the inset,no lattice defects can be observed.

Fig.2(a)shows AFM image of Ag NP array fabricated on a glass substrate using the established NSL process after removing the nanosphere templates.The produced Ag NPs show hexagonally arranged triangular nanoprisms.The magni?ed image in the insert shows that for some NPs their tips and edges have many defects due to NP damage during liftoff by sonication.From the three-dimensional(3D)images for some of these Ag NPs(Fig.2(b)),it can be clearly seen that the Ag NPs are triangular nanoprisms with increased thickness from edges to the center(~30±0.5nm).How-ever,as observed in the insert of Fig.2(a),many of the NPs show rough surface morphology.Nanoparticle tips or edges form weak parts in the NPs which can easily break during sonication.This sig-ni?cantly reduces the shape uniformity of the NPs and produce debris in the solution.Transmission electron microscopy(TEM) images for these aqueous phase NPs show many small NPs present with prism shape(Fig.2(c)).The calculated edge size of the triangu-lar prism NPs is~78nm when using290nm diameter nanospheres. This size is consistent with that observed from the AFM images of unreleased NPs shown in Fig.2(a)and(b).For the released NPs, the TEM image in Fig.2(c)shows the expected triangular prism shape(dashed ellipses)and some small irregular spherical shaped NPs(dotted circles).Their size distributions are shown in Fig.2(d) and(e).For the triangular prism NPs,a broad size distribution of 74.3±31.0nm(in addition to some smaller triangular NPs with an edge size of~20–30nm)is observed.The circular NPs had a size distribution of10.0±4.6nm.The Ag NPs observed with one or two truncated tips(some of the dashed ellipse)are broken tips from the original NPs produced by nanosphere lithography.Some of these triangular prism NPs have rough surfaces and their thickness varies considerably over the triangular surface of the NPs(shown in the inset).This roughness appears to be caused by NP damage during sonication.

These size and shape features of the aqueous phase NPs are also re?ected by their UV–vis absorption spectrum,which shows two distinct absorption peaks centered at~352nm and~605nm,as shown in Fig.2(f).It is surprising that one peak at352nm appears in our aqueous-phased Ag NPs released from the surface-con?ned Ag NPs fabricated by the routine nanosphere lithography(NSL)since it is common for small Ag NPs(<10nm)to have a LSPR peak over 400nm(e.g.410–420nm),which was often observed in Ag NPs synthesized by wet chemical methods(e.g.Ag salt reduction)using different surfactants[17–19].In the work of Amanda et al.,one of the LSPR peaks for the ethanol-phase hexadecanethiol coated Ag NPs fabricated by the routine NSL is also observed to be longer than 400nm[15].These NPs had heights of52nm and widths of100nm [15].In our case,~60nm blue shift in LSPR compared to the LSPR in Ref.[15].LSPR peaks at340nm or350nm and380nm have pre-viously been observed for Ag nanoplates with size of100–300nm and thickness of10–20nm,which were attributed to out-of-plane quadrupole resonance and out-of-plane dipole resonance,respec-tively[14,19].Since the height of our NPs(30nm)is larger than those reported in Ref.[19](16nm),the out-of-plane quadrupole resonance at352from our nanoprisms become signi?cant.Fur-thermore,the presence of small spherical NPs(2–10nm,as shown Fig.2(c)and(e))in our aqueous Ag NPs solution could contribute to the observed LSPR spectrum.These small NPs are expected to give a LSPR at~410–420nm[17,18],resulting in the broadening of the peak at352nm,as observed in Fig.2(f).Therefore,the broad peak at352nm in Fig.2(f)(ranging from330nm to430nm)could be interpreted as representing the combination of the out-of-plane dipole resonance and the out-of-plane quadrupole resonance of the Ag nanoprisms and the contribution of small debris,which is often observed together with the dipole LSPR at605nm in our nanoprism solution.The intensity ratio of the peak at~350nm to that at~605nm is~3.6:1.The relative strength of the short wave-length peak is consistent with the high density of small-size NPs produced as debris during sonication.Therefore,both TEM analy-sis and absorption measurement show that the routine NSL and NP release process yields a wide distribution of NP sizes and shapes.

In order to reduce the breakage of NPs during sonication,we investigated modi?cations to the routine NSL process.Thermal annealing of the NPs fabricated by NSL prior to releasing them in a solution was investigated as a means to reduce internal stresses in the NPs and round the sharp weak edges by solid-state diffusion. Subsequent washing by diluted nitric acid was also investigated as a method to dissolve the debris around the NPs and remove any sur-face https://www.wendangku.net/doc/3318789880.html,paring the AFM images in Fig.2(a)and(b), showing the NPs without thermal annealing,to Fig.3(a-1),show-ing the NPs after annealing at200?C and subsequent washing with 5%nitric acid,we observe that thermal annealing results in much more uniform NP surfaces without the thin,weak tips and edges. From the magni?ed AFM image in the inset of Fig.3(a-1)and the 3D image in Fig.3(a-2),the NPs still show triangular prism shape with rounded edges and without obvious surface defects.

Alternatively,if we sonicate the NPs produced by NSL for ~30–45s to remove a weak tip,anneal them at200?C for4h, then wash them with5%nitric acid,trapezoidal shaped NPs with rounded edges are formed,as shown in Fig.3(b-1)and(b-2).If the sonication time is increased to more than2min,the NPs lose their two sharp tips and form quadrilateral or pentagon-shaped NPs. After thermal annealing for4h and washing with5%nitric acid, their edges and corners become rounded,as shown in Fig.3(c-1) which show quadrilateral NPs(in dashed squares)or pentagon(in dashed circles).The3D AFM image,Fig.3(c-2),shows that these NPs have rounded edges and corners.However,even after ther-

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Fig.2.Ag NPs fabricated by the routine NSL process.(a)AFM image of an area of surface-con?ned triangular prism Ag NPs.The inserted magni?ed image shows the weak tips and rough surface morphologies.(b)3D AFM image of the triangular prism NPs.(c)TEM images of the released aqueous phase Ag NPs show different kinds of NPs:some are the triangular prism Ag NPs with or without truncated tips(labeled with dashed ellipses and shown in the top-right inset)and some are the small NPs from debris produced during sonication(some irregular spherical debris labeled with dotted circles and some small triangular debris from broken tips of the triangular nanoprisms labeled by dashed squares).(d)Histogram of triangular shaped Ag NPs gives mean sizes of74.3±31.0nm.(e)Histogram of the irregular spherical shaped Ag NPs gives mean sizes of 10.0±4.6nm.(f)The UV–vis absorption spectrum for the aqueous phase NPs show two distinct peaks;one sharp peak at352nm from the combined contribution of the LSPR of the small Ag NPs and the high-mode LSPR of the triangular Ag NPs,another broad peak at605nm mainly from the dipole LSPR of the triangular Ag NPs.

Fig.3.Surface-con?ned Ag NPs with controlled shapes fabricated by the modi?ed NSL process.(a-1)AFM image of triangular prism Ag NPs with rounded tips after thermal annealing at200?C for4h,cleaning by5%nitric acid,and washing by nanopure water.(a-2)The3D image of the triangular prism Ag NPs with rounded tips.(b-1)Flat trapezoidal Ag NPs after sonication to remove one tip,thermal annealing,cleaning by5%nitric acid,and washing by nanopure water.(b-2)The3D image of the trapezoidal Ag NPs with one snipped tip.(c-1)The quadrilateral or pentagon-shaped Ag NPs after sonication intensively to remove two tips,thermal annealing,cleaning by5%nitric acid and washing by nanopure water.Dashed circles:pentagonal Ag NPs with one sharp tip left;dashed squares:quadrilateral Ag NPs.(c-2)is the3D image of the quadrilateral and pentagon-shaped Ag NPs.

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Fig.4.TEM images of the aqueous phase Ag NPs after surface modi?cation by thiol compounds and dislodging from the glass substrate.(a)Triangle Ag NPs with rounded tips.Dashed circles:Ag NPs with rounded tips;dotted circle:Ag NPs with slightly rounded tips.(b)Histogram of triangular shaped Ag NPs with rounded tips based on45 NPs giving a mean size of39.6±4.9nm.(c)Quadrilateral and pentagon-shaped Ag NPs.Dashed circles:some typical Ag NPs with quadrilateral shapes.(d)Histogram of quadrilateral and pentagon-shaped Ag NPs based on45NPs giving a mean size of33.9±6.8nm.

mal annealing,they are still showing prism shapes with increased thickness from their edges to centers.Further sonication for2min followed by annealing at200?C for~4h resulted in hexagonal shaped NPs with rounded corners and edges.

We next investigated the shape integrity of the heat-treated NPs after releasing them into water.Fig.4(a)shows TEM image of the Ag NPs after thermal annealing without pre-sonication.Most of those Ag NPs show triangular shapes with rounded tips(doted circles in Fig.4(a))and some with snipped tips(dashed circles in Fig.4(a)).The inset is a magni?ed image of these NPs,clearly show-ing a triangular shape with rounded tips.The histogram for these Ag NPs(Fig.4(b))gives a mean size of39.6±4.9nm with much nar-rower size distribution of STDEV%=12.4%than those obtained from surface-con?ned Ag NPs without any post-annealing(Fig.2(d), STDEV%=41.7%).Fig.4(c)is a TEM image for Ag NPs that were thermally annealed after removing two tips by sonication,whose histogram gives a mean size of about33.9±6.8nm(Fig.4(d)), less than that for those triangular shaped NPs with rounded tips after post-annealing.Most of these NPs show quadrilateral shapes (dashed circles)or pentagon shapes as shown more clearly in the inset of Fig.4(c).These NPs have a similar shape as those observed by AFM images in Fig.3(c-1)and(c-2).From the TEM images in Fig.4(c),some of the NPs give less contrast in their central parts (NPs labeled by dashed circles).We believe that the lighter centers in these NPs are from a thinner center resulting from adhesion of the center of these NPs to the glass substrate during annealing.AFM observation of the glass substrate after removal of the NPs show debris forming hexagonal shaped arrangements.This observation is consistent with adhesion of the central part of the triangular prism NPs to the substrate.The UV–vis absorption spectra of the surface-con?ned NPs change signi?cantly before and after surface modi?cation.Fig.5(a)shows the absorption spectrum of surface-con?ned Ag NPs fabricated by NSL without any modi?cation.It can be seen that the absorption spectrum for the Ag NPs gives two dis-tinct peaks at476nm and672nm.Based on previous investigation on these NPs and their arrays[15,19,20],it is reasonable to expect that the absorption peak at476nm is primarily from the higher order mode surface plasmon resonance(e.g.quadrupole)of the NPs, and the peak at672nm is primarily from the dipole resonance of the NPs.We note that the higher order resonance peak has almost the same intensity as that for the dipole resonance,although the

higher

Fig.5.Optical absorption of Ag NPs.(a)Surface-con?ned Ag NPs before surface modi?cation.(b)Surface-con?ned Ag NPs after surface modi?cation with thiol.(c) Aqueous phase Ag NPs after releasing the surface-con?ned NPs into water.

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xxx (2010) xxx–xxx

Fig.6.XPS spectrum for the surface-con?ned Ag NPs after surface modi?cation by 1-OT and11-MUA.

order modes are expected to be much weaker than the dipole reso-nance.Since the substrate is continuously covered by a hexagonally arranged array of Ag NPs with tip–tip distance less than100nm, we postulate that particle–particle coupling will contribute to the LSPR spectrum.This particle–particle interaction effect could be responsible for the observed spectrum.

Before releasing the Ag NPs into water,their surfaces must be modi?ed by a water-soluble stabilizer.We used the combination of1-OT and11-MUA.The surface modi?cation of the Ag NPs was conducted using the routine thiol coupling chemistry as described in Section2.In order to con?rm that the thiol compounds are linked on the Ag NPs,X-ray photoelectron spectroscopy(XPS)spectrum for the surface-con?ned Ag NPs after modi?cation by1-OT and11-MUA was obtained.Before XPS was performed,the glass substrate with the modi?ed Ag NPs was thoroughly washed by ethanol to remove the unbound thiol compounds(1-OT,11-MUA,etc.).The obtained XPS spectrum in Fig.6shows binding energy peaks for Ag3s(700eV),Ag3p1(608eV),Ag3p3(578eV),Ag3d3(376eV), Ag3d5(375eV),Ag4s(334eV),Ag4p(69eV)in addition to peaks for C1s(292eV),C2s(15eV),O1s(537eV),S2p(170eV)originating from the thiol compounds.The height of the Ag NPs before and after the thiol modi?cation was also measured by AFM and was observed to increase by~2.9nm after the thiol modi?cation.Since the cal-culated height of MUA is~1.7nm,the adsorbate may be one layer formed by mono or double assembly of MUA and1-OT molecules. The variation between the calculation and the AFM result may be resulted from the height increase of NPs during immersion in the thiol solution,similar as the solvent annealing effect[21–23].These experimental results con?rm that at least one layer of thiol com-pounds is bonded on the Ag NP surface.

Since this adsorbed layer is only~2.9nm thick,it is not expected to produce signi?cant change to the surface dielectric properties of the Ag NPs.However,the silver–sulfur bonding between the NPs and the thiol compounds may affect the conductivity and the num-ber of free surface electrons in the Ag NPs.The absorption spectrum for the modi?ed Ag NPs(Fig.5(b))shows a slight blue shift at the peak at476nm(to470nm)and a signi?cant blue shift at672nm (to626nm)with reduced intensities.This spectrum was expected to give a red shift due to the increased dielectric constant from the adsorbed thiol compounds[15].We attribute this blue shift to shape variation(e.g.increased height,rounded tips,smoother sur-face topography)during surface modi?cation by immersion that was similar to solvent annealing which results in blue shift of LSPR since any solvent annealing has not been done on our NPs[21–23]. These variations are further observed by the slightly reduced NP size and rounded shapes observed in the TEM image of Fig.4 when compared with the AFM image of Fig.3.In addition,when the Ag NPs are covered by thiol groups,the surface free electron density may be reduced,leading to weaker surface plasmon reso-nance in single NPs and surface plasmon resonance coupling among nanoparticle arrays[24].This will also result in a blue shift of the LSPR peak and a reduced LSPR intensity.

The UV–vis absorption spectrum of the Ag NPs after release in water,shown in Fig.5(c),was compared to surface-con?ned NPs.The aqueous Ag NPs give a main peak at532nm and a very weak peak at352nm.The main peak at532nm appears to be from LSPR by the triangular prism NPs with rounded tips and is blue shifted from that obtained for NPs fabricated by the routine NSL and released from the surface that showed LSPR peak605nm.This is attributed to the reduced size and rounded tips.The peak at352nm in Fig.5(c)becomes much weaker and narrower than that for the aqueous Ag NPs released from the surface-con?ned Ag NPs as fab-ricated by routine NSL(shown in Fig.2(f)),obviously due to the shape variation of NPs and almost no small spherical shaped debris observed in the aqueous Ag NPs released from the surface-con?ned Ag NPs fabricated by the modi?ed NSL(Fig.5a).By comparing the TEM images for the two kinds of Ag NPs,it can be deduced that the peak at352nm in Fig.5(c)is mainly from the out-of-plane quadrupole resonance of Ag nanoprisms with rounded tips accord-ing to previous investigation[14,15,19].The peak intensity ratio between the main peak at532nm and the weak peak at352nm for these NPs is~11.5:1(after subtracting the background),which is much higher than that for the NPs obtained by the routine NSL and releasing process(1:3.6).Clearly,the number of small debris caused by sonication is greatly reduced using the modi?ed NSL and releasing process.The modi?ed NSL process favors the formation of uniform Ag NPs with rounded tips with signi?cant reduction in Ag debris,as shown in Fig.4.In addition,1-OT and11-MUA can be substituted by the combination of1-BT and TP,or MCH and MUA for more water-soluble NPs.

4.Summary

Ag NPs with controlled shapes and reduced defect density were fabricated by a modi?ed NSL process based upon thermal anneal-ing the Ag NPs,sonication to remove weak tips,slight etching of the substrate under the NPs,and cleaning the substrates using 2–5%nitric acid,followed by washing using suf?cient nanopure water.Upon dislodging these NPs into a solution,they retain their shapes signi?cantly better than NPs produced by routine NSL.Thus, aqueous phase Ag NPs with relatively uniform size and shape distribution can be fabricated.The UV–vis absorption spectra for surface-con?ned NPs show two distinct absorption peaks.After surface modi?cation,the central wavelengths of the two absorption peaks blue shifted and showed reduced intensities.The aqueous-phased Ag NPs produced by the modi?ed NSL method show a main peak and another peak with very low intensity attributed mainly to small debris produced during the dislodging process.The notice-able reduction in the intensity of the short wavelength peak for the modi?ed NSL method compared to the routine method is due to the signi?cant reduction in Ag debris.TEM images show that the modi?ed NSL and releasing processes can produce signi?cant improvement in Ag NPs uniformity.

Acknowledgements

Y.Song appreciates support from New Teacher Funds(2008-00061025)the Scienti?c Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry,Research Developing Funds for Imported Talents(211109)at Beihang University and Innovative Research Team of Chinese Education Ministry in University(IRT0512).H.E.Elsayed-Ali acknowledges support from US National Science Foundation NIRT grant NSF-0507036.

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with复合结构专项练习96126

with复合结构专项练习(二) 一请选择最佳答案 1)With nothing_______to burn,the fire became weak and finally died out. A.leaving B.left C.leave D.to leave 2)The girl sat there quite silent and still with her eyes_______on the wall. A.fixing B.fixed C.to be fixing D.to be fixed 3)I live in the house with its door_________to the south.(这里with结构作定语) A.facing B.faces C.faced D.being faced 4)They pretended to be working hard all night with their lights____. A.burn B.burnt C.burning D.to burn 二:用with复合结构完成下列句子 1)_____________(有很多工作要做),I couldn't go to see the doctor. 2)She sat__________(低着头)。 3)The day was bright_____.(微风吹拂) 4)_________________________,(心存梦想)he went to Hollywood. 三把下列句子中的划线部分改写成with复合结构。 1)Because our lessons were over,we went to play football. _____________________________. 2)The children came running towards us and held some flowers in their hands. _____________________________. 3)My mother is ill,so I won't be able to go on holiday. _____________________________. 4)An exam will be held tomorrow,so I couldn't go to the cinema tonight. _____________________________.

With的用法全解

With的用法全解 with结构是许多英语复合结构中最常用的一种。学好它对学好复合宾语结构、不定式复合结构、动名词复合结构和独立主格结构均能起很重要的作用。本文就此的构成、特点及用法等作一较全面阐述,以帮助同学们掌握这一重要的语法知识。 一、 with结构的构成 它是由介词with或without+复合结构构成,复合结构作介词with或without的复合宾语,复合宾语中第一部分宾语由名词或代词充当,第二部分补足语由形容词、副词、介词短语、动词不定式或分词充当,分词可以是现在分词,也可以是过去分词。With结构构成方式如下: 1. with或without-名词/代词+形容词; 2. with或without-名词/代词+副词; 3. with或without-名词/代词+介词短语; 4. with或without-名词/代词 +动词不定式; 5. with或without-名词/代词 +分词。 下面分别举例: 1、 She came into the room,with her nose red because of cold.(with+名词+形容词,作伴随状语)

2、 With the meal over , we all went home.(with+名词+副词,作时间状语) 3、The master was walking up and down with the ruler under his arm。(with+名词+介词短语,作伴随状语。) The teacher entered the classroom with a book in his hand. 4、He lay in the dark empty house,with not a man ,woman or child to say he was kind to me.(with+名词+不定式,作伴随状语)He could not finish it without me to help him.(without+代词 +不定式,作条件状语) 5、She fell asleep with the light burning.(with+名词+现在分词,作伴随状语) Without anything left in the with结构是许多英 语复合结构中最常用的一种。学好它对学好复合宾语结构、不定式复合结构、动名词复合结构和独立主格结构均能起很重要的作用。本文就此的构成、特点及用法等作一较全面阐述,以帮助同学们掌握这一重要的语法知识。 二、with结构的用法 with是介词,其意义颇多,一时难掌握。为帮助大家理清头绪,以教材中的句子为例,进行分类,并配以简单的解释。在句子中with结构多数充当状语,表示行为方式,伴随情况、时间、原因或条件(详见上述例句)。 1.带着,牵着…… (表动作特征)。如: Run with the kite like this.

精神分裂症的病因及发病机理

精神分裂症的病因及发病机理 精神分裂症病因:尚未明,近百年来的研究结果也仅发现一些可能的致病因素。(一)生物学因素1.遗传遗传因素是精神分裂症最可能的一种素质因素。国内家系调查资料表明:精神分裂症患者亲属中的患病率比一般居民高6.2倍,血缘关系愈近,患病率也愈高。双生子研究表明:遗传信息几乎相同的单卵双生子的同病率远较遗传信息不完全相同 的双卵双生子为高,综合近年来11项研究资料:单卵双生子同病率(56.7%),是双卵双生子同病率(12.7%)的4.5倍,是一般人口患难与共病率的35-60倍。说明遗传因素在本病发生中具有重要作用,寄养子研究也证明遗传因素是本症发病的主要因素,而环境因素的重要性较小。以往的研究证明疾病并不按类型进行遗传,目前认为多基因遗传方式的可能性最大,也有人认为是常染色体单基因遗传或多源性遗传。Shields发现病情愈轻,病因愈复杂,愈属多源性遗传。高发家系的前瞻性研究与分子遗传的研究相结合,可能阐明一些问题。国内有报道用人类原癌基因Ha-ras-1为探针,对精神病患者基因组进行限止性片段长度多态性的分析,结果提示11号染色体上可能存在着精神分裂症与双相情感性精神病有关的DNA序列。2.性格特征:约40%患者的病前性格具有孤僻、冷淡、敏感、多疑、富于幻想等特征,即内向

型性格。3.其它:精神分裂症发病与年龄有一定关系,多发生于青壮年,约1/2患者于20~30岁发病。发病年龄与临床类型有关,偏执型发病较晚,有资料提示偏执型平均发病年龄为35岁,其它型为23岁。80年代国内12地区调查资料:女性总患病率(7.07%。)与时点患病率(5.91%。)明显高于男性(4.33%。与3.68%。)。Kretschmer在描述性格与精神分裂症关系时指出:61%患者为瘦长型和运动家型,12.8%为肥胖型,11.3%发育不良型。在躯体疾病或分娩之后发生精神分裂症是很常见的现象,可能是心理性生理性应激的非特异性影响。部分患者在脑外伤后或感染性疾病后发病;有报告在精神分裂症患者的脑脊液中发现病毒性物质;月经期内病情加重等躯体因素都可能是诱发因素,但在精神分裂症发病机理中的价值有待进一步证实。(二)心理社会因素1.环境因素①家庭中父母的性格,言行、举止和教育方式(如放纵、溺爱、过严)等都会影响子女的心身健康或导致个性偏离常态。②家庭成员间的关系及其精神交流的紊乱。③生活不安定、居住拥挤、职业不固定、人际关系不良、噪音干扰、环境污染等均对发病有一定作用。农村精神分裂症发病率明显低于城市。2.心理因素一般认为生活事件可发诱发精神分裂症。诸如失学、失恋、学习紧张、家庭纠纷、夫妻不和、意处事故等均对发病有一定影响,但这些事件的性质均无特殊性。因此,心理因素也仅属诱发因

with用法归纳

with用法归纳 (1)“用……”表示使用工具,手段等。例如: ①We can walk with our legs and feet. 我们用腿脚行走。 ②He writes with a pencil. 他用铅笔写。 (2)“和……在一起”,表示伴随。例如: ①Can you go to a movie with me? 你能和我一起去看电影'>电影吗? ②He often goes to the library with Jenny. 他常和詹妮一起去图书馆。 (3)“与……”。例如: I’d like to have a talk with you. 我很想和你说句话。 (4)“关于,对于”,表示一种关系或适应范围。例如: What’s wrong with your watch? 你的手表怎么了? (5)“带有,具有”。例如: ①He’s a tall kid with short hair. 他是个长着一头短发的高个子小孩。 ②They have no money with them. 他们没带钱。 (6)“在……方面”。例如: Kate helps me with my English. 凯特帮我学英语。 (7)“随着,与……同时”。例如: With these words, he left the room. 说完这些话,他离开了房间。 [解题过程] with结构也称为with复合结构。是由with+复合宾语组成。常在句中做状语,表示谓语动作发生的伴随情况、时间、原因、方式等。其构成有下列几种情形: 1.with+名词(或代词)+现在分词 此时,现在分词和前面的名词或代词是逻辑上的主谓关系。 例如:1)With prices going up so fast, we can't afford luxuries. 由于物价上涨很快,我们买不起高档商品。(原因状语) 2)With the crowds cheering, they drove to the palace. 在人群的欢呼声中,他们驱车来到皇宫。(伴随情况) 2.with+名词(或代词)+过去分词 此时,过去分词和前面的名词或代词是逻辑上的动宾关系。

独立主格with用法小全

独立主格篇 独立主格,首先它是一个“格”,而不是一个“句子”。在英语中任何一个句子都要有主谓结构,而在这个结构中,没有真正的主语和谓语动词,但又在逻辑上构成主谓或主表关系。独立主格结构主要用于描绘性文字中,其作用相当于一个状语从句,常用来表示时间、原因、条件、行为方式或伴随情况等。除名词/代词+名词、形容词、副词、非谓语动词及介词短语外,另有with或without短语可做独立主格,其中with可省略而without不可以。*注:独立主格结构一般放在句首,表示原因时还可放在句末;表伴随状况或补充说明时,相当于一个并列句,通常放于句末。 一、独立主格结构: 1. 名词/代词+形容词 He sat in the front row, his mouth half open. Close to the bank I saw deep pools, the water blue like the sky. 靠近岸时,我看见几汪深池塘,池水碧似蓝天。 2. 名词/代词+现在分词 Winter coming, it gets colder and colder. The rain having stopped, he went out for a walk.

The question having been settled, we wound up the meeting. 也可以The question settled, we wound up the meeting. 但含义稍有差异。前者强调了动作的先后。 We redoubled our efforts, each man working like two. 我们加倍努力,一个人干两个人的活。 3. 名词/代词+过去分词 The job finished, we went home. More time given, we should have done the job much better. *当表人体部位的词做逻辑主语时,不及物动词用现在分词,及物动词用过去分词。 He lay there, his teeth set, his hands clenched, his eyes looking straight up. 他躺在那儿,牙关紧闭,双拳紧握,两眼直视上方。 4. 名词/代词+不定式 We shall assemble at ten forty-five, the procession to start moving at precisely eleven. We divided the work, he to clean the windows and I to sweep the floor.

精神分裂症的发病原因是什么

精神分裂症的发病原因是什么 精神分裂症是一种精神病,对于我们的影响是很大的,如果不幸患上就要及时做好治疗,不然后果会很严重,无法进行正常的工作和生活,是一件很尴尬的事情。因此为了避免患上这样的疾病,我们就要做好预防,今天我们就请广州协佳的专家张可斌来介绍一下精神分裂症的发病原因。 精神分裂症是严重影响人们身体健康的一种疾病,这种疾病会让我们整体看起来不正常,会出现胡言乱语的情况,甚至还会出现幻想幻听,可见精神分裂症这种病的危害程度。 (1)精神刺激:人的心理与社会因素密切相关,个人与社会环境不相适应,就产生了精神刺激,精神刺激导致大脑功能紊乱,出现精神障碍。不管是令人愉快的良性刺激,还是使人痛苦的恶性刺激,超过一定的限度都会对人的心理造成影响。 (2)遗传因素:精神病中如精神分裂症、情感性精神障碍,家族中精神病的患病率明显高于一般普通人群,而且血缘关系愈近,发病机会愈高。此外,精神发育迟滞、癫痫性精神障碍的遗传性在发病因素中也占相当的比重。这也是精神病的病因之一。 (3)自身:在同样的环境中,承受同样的精神刺激,那些心理素质差、对精神刺激耐受力低的人易发病。通常情况下,性格内向、心胸狭窄、过分自尊的人,不与人交往、孤僻懒散的人受挫折后容易出现精神异常。 (4)躯体因素:感染、中毒、颅脑外伤、肿瘤、内分泌、代谢及营养障碍等均可导致精神障碍,。但应注意,精神障碍伴有的躯体因素,并不完全与精神症状直接相关,有些是由躯体因素直接引起的,有些则是以躯体因素只作为一种诱因而存在。 孕期感染。如果在怀孕期间,孕妇感染了某种病毒,病毒也传染给了胎儿的话,那么,胎儿出生长大后患上精神分裂症的可能性是极其的大。所以怀孕中的女性朋友要注意卫生,尽量不要接触病毒源。 上述就是关于精神分裂症的发病原因,想必大家都已经知道了吧。患上精神分裂症之后,大家也不必过于伤心,现在我国的医疗水平是足以让大家快速恢复过来的,所以说一定要保持良好的情绪。

with复合宾语的用法(20201118215048)

with+复合宾语的用法 一、with的复合结构的构成 二、所谓"with的复合结构”即是"with+复合宾语”也即"with +宾语+宾语补足语” 的结构。其中的宾语一般由名词充当(有时也可由代词充当);而宾语补足语则是根据 具体的需要由形容词,副词、介词短语,分词短语(包括现在分词和过去分词)及不定式短语充当。下面结合例句就这一结构加以具体的说明。 三、1、with +宾语+形容词作宾补 四、①He slept well with all the windows open.(82 年高考题) 上面句子中形容词open作with的宾词all the windows的补足语, ②It' s impolite to talk with your mouth full of food. 形容词短语full of food 作宾补。Don't sleep with the window ope n in win ter 2、with+宾语+副词作宾补 with Joh n away, we have got more room. He was lying in bed with all his clothes on. ③Her baby is used to sleeping with the light on.句中的on 是副词,作宾语the light 的补足语。 ④The boy can t play with his father in.句中的副词in 作宾补。 3、with+宾语+介词短语。 we sat on the grass with our backs to the wall. his wife came dow n the stairs,with her baby in her arms. They stood with their arms round each other. With tears of joy in her eyes ,she saw her daughter married. ⑤She saw a brook with red flowers and green grass on both sides. 句中介词短语on both sides 作宾语red flowersandgreen grass 的宾补, ⑥There were rows of white houses with trees in front of them.,介词短语in front of them 作宾补。 4、with+宾词+分词(短语 这一结构中作宾补用的分词有两种,一是现在分词,二是过去分词,一般来说,当分词所表 示的动作跟其前面的宾语之间存在主动关系则用现在分词,若是被动关系,则用过去分词。 ⑦In parts of Asia you must not sit with your feet pointing at another person.(高一第十课),句中用现在分词pointing at…作宾语your feet的补足语,是因它们之间存在主动关系,或者说point 这一动作是your feet发出的。 All the after noon he worked with the door locked. She sat with her head bent. She did not an swer, with her eyes still fixed on the wall. The day was bright,with a fresh breeze(微风)blowing. I won't be able to go on holiday with my mother being ill. With win ter coming on ,it is time to buy warm clothes. He soon fell asleep with the light still bur ning. ⑧From space the earth looks like ahuge water covered globe,with a few patches of land stuk ing out above the water而在下面句子中因with的宾语跟其宾补之间存在被动关系,故用过去分词作宾补:

with用法小结

with用法小结 一、with表拥有某物 Mary married a man with a lot of money . 马莉嫁给了一个有着很多钱的男人。 I often dream of a big house with a nice garden . 我经常梦想有一个带花园的大房子。 The old man lived with a little dog on the lonely island . 这个老人和一条小狗住在荒岛上。 二、with表用某种工具或手段 I cut the apple with a sharp knife . 我用一把锋利的刀削平果。 Tom drew the picture with a pencil . 汤母用铅笔画画。 三、with表人与人之间的协同关系 make friends with sb talk with sb quarrel with sb struggle with sb fight with sb play with sb work with sb cooperate with sb I have been friends with Tom for ten years since we worked with each other, and I have never quarreled with him . 自从我们一起工作以来,我和汤姆已经是十年的朋友了,我们从没有吵过架。 四、with 表原因或理由 John was in bed with high fever . 约翰因发烧卧床。 He jumped up with joy . 他因高兴跳起来。 Father is often excited with wine . 父亲常因白酒变的兴奋。 五、with 表“带来”,或“带有,具有”,在…身上,在…身边之意

精神分裂症的病因是什么

精神分裂症的病因是什么 精神分裂症是一种精神方面的疾病,青壮年发生的概率高,一般 在16~40岁间,没有正常器官的疾病出现,为一种功能性精神病。 精神分裂症大部分的患者是由于在日常的生活和工作当中受到的压力 过大,而患者没有一个良好的疏导的方式所导致。患者在出现该情况 不仅影响本人的正常社会生活,且对家庭和社会也造成很严重的影响。 精神分裂症常见的致病因素: 1、环境因素:工作环境比如经济水平低低收入人群、无职业的人群中,精神分裂症的患病率明显高于经济水平高的职业人群的患病率。还有实际的生活环境生活中的不如意不开心也会诱发该病。 2、心理因素:生活工作中的不开心不满意,导致情绪上的失控,心里长期受到压抑没有办法和没有正确的途径去发泄,如恋爱失败, 婚姻破裂,学习、工作中不愉快都会成为本病的原因。 3、遗传因素:家族中长辈或者亲属中曾经有过这样的病人,后代会出现精神分裂症的机会比正常人要高。 4、精神影响:人的心里与社会要各个方面都有着不可缺少的联系,对社会环境不适应,自己无法融入到社会中去,自己与社会环境不相

适应,精神和心情就会受到一定的影响,大脑控制着人的精神世界, 有可能促发精神分裂症。 5、身体方面:细菌感染、出现中毒情况、大脑外伤、肿瘤、身体的代谢及营养不良等均可能导致使精神分裂症,身体受到外界环境的 影响受到一定程度的伤害,心里受到打击,无法承受伤害造成的痛苦,可能会出现精神的问题。 对于精神分裂症一定要配合治疗,接受全面正确的治疗,最好的 疗法就是中医疗法加心理疗法。早发现并及时治疗并且科学合理的治疗,不要相信迷信,要去正规的医院接受合理的治疗,接受正确的治 疗按照医生的要求对症下药,配合医生和家人,给病人创造一个良好 的治疗环境,对于该病的康复和痊愈会起到意想不到的效果。

(完整版)with的复合结构用法及练习

with复合结构 一. with复合结构的常见形式 1.“with+名词/代词+介词短语”。 The man was walking on the street, with a book under his arm. 那人在街上走着,腋下夹着一本书。 2. “with+名词/代词+形容词”。 With the weather so close and stuffy, ten to one it’ll rain presently. 天气这么闷热,十之八九要下雨。 3. “with+名词/代词+副词”。 The square looks more beautiful than even with all the light on. 所有的灯亮起来,广场看起来更美。 4. “with+名词/代词+名词”。 He left home, with his wife a hopeless soul. 他走了,妻子十分伤心。 5. “with+名词/代词+done”。此结构过去分词和宾语是被动关系,表示动作已经完成。 With this problem solved, neomycin 1 is now in regular production. 随着这个问题的解决,新霉素一号现在已经正式产生。 6. “with+名词/代词+-ing分词”。此结构强调名词是-ing分词的动作的发出者或某动作、状态正在进行。 He felt more uneasy with the whole class staring at him. 全班同学看着他,他感到更不自然了。 7. “with+宾语+to do”。此结构中,不定式和宾语是被动关系,表示尚未发生的动作。 So in the afternoon, with nothing to do, I went on a round of the bookshops. 由于下午无事可做,我就去书店转了转。 二. with复合结构的句法功能 1. with 复合结构,在句中表状态或说明背景情况,常做伴随、方式、原因、条件等状语。With machinery to do all the work, they will soon have got in the crops. 由于所有的工作都是由机器进行,他们将很快收完庄稼。(原因状语) The boy always sleeps with his head on the arm. 这个孩子总是头枕着胳膊睡觉。(伴随状语)The soldier had him stand with his back to his father. 士兵要他背对着他父亲站着。(方式状语)With spring coming on, trees turn green. 春天到了,树变绿了。(时间状语) 2. with 复合结构可以作定语 Anyone with its eyes in his head can see it’s exactly like a rope. 任何一个头上长着眼睛的人都能看出它完全像一条绳子。 【高考链接】 1. ___two exams to worry about, I have to work really hard this weekend.(04北京) A. With B. Besides C. As for D. Because of 【解析】A。“with+宾语+不定式”作状语,表示原因。 2. It was a pity that the great writer died, ______his works unfinished. (04福建) A. for B. with C. from D.of 【解析】B。“with+宾语+过去分词”在句中作状语,表示状态。 3._____production up by 60%, the company has had another excellent year. (NMET) A. As B.For C. With D.Through 【解析】C。“with+宾语+副词”在句中作状语,表示程度。

With复合结构的用法小结

With复合结构的用法小结 with结构是许多英语复合结构中最常用的一种。学好它对学好复合宾语结构、不定式复合结构、动名词复合结构和独立主格结构均能起很重要的作用。本文就此的构成、特点及用法等作一较全面阐述,以帮助同学们掌握这一重要的语法知识。 一、with结构的构成 它是由介词with或without+复合结构构成,复合结构作介词with或without的复合宾语,复合宾语中第一部分宾语由名词或代词充当,第二 部分补足语由形容词、副词、介词短语、动词不定式或分词充当,分词可以是现在分词,也可以是过去分词。With结构构成方式如下: 1. with或without-名词/代词+形容词; 2. with或without-名词/代词+副词; 3. with或without-名词/代词+介词短语; 4. with或without-名词/代词+动词不定式; 5. with或without-名词/代词+分词。 下面分别举例: 1、She came into the room,with her nose red because of cold.(with+名词+形容词,作伴随状语) 2、With the meal over ,we all went home.(with+名词+副词,作时间状语) 3、The master was walking up and down with the ruler under his arm。(with+名词+介词短语,作伴随状语。)The teacher entered the classroom with a book in his hand. 4、He lay in the dark empty house,with not a man ,woman or child to say he was kind to me.(with+名词+不定式,作伴随状语)He could not finish it without me to help him.(without+代词+不定式,作条件状语) 5、She fell asleep with the light burning.(with+名词+现在分词,作伴随状语)Without anything left in the cupboard,shewent out to get something to eat.(without+代词+过去分词,作为原因状语) 二、with结构的用法 在句子中with结构多数充当状语,表示行为方式,伴随情况、时间、原因或条件(详见上述例句)。 With结构在句中也可以作定语。例如: 1.I like eating the mooncakes with eggs. 2.From space the earth looks like a huge water-covered globe with a few patches of land sticking out above the water. 3.A little boy with two of his front teeth missing ran into the house. 三、with结构的特点 1. with结构由介词with或without+复合结构构成。复合结构中第一部分与第二部分语法上是宾语和宾语补足语关系,而在逻辑上,却具有主谓关系,也就是说,可以用第一部分作主语,第二部分作谓语,构成一个句子。例如:With him taken care of,we felt quite relieved.(欣慰)→(He was taken good care of.)She fell asleep with the light burning. →(The light was burning.)With her hair gone,there could be no use for them. →(Her hair was gone.) 2. 在with结构中,第一部分为人称代词时,则该用宾格代词。例如:He could not finish it without me to help him. 四、几点说明: 1. with结构在句子中的位置:with 结构在句中作状语,表示时间、条件、原因时一般放在

with的用法

with[wIT] prep.1.与…(在)一起,带着:Come with me. 跟我一起来吧。/ I went on holiday with my friend. 我跟我朋友一起去度假。/ Do you want to walk home with me? 你愿意和我一道走回家吗 2.(表带有或拥有)有…的,持有,随身带着:I have no money with me. 我没有带钱。/ He is a man with a hot temper. 他是一个脾气暴躁的人。/ We bought a house with a garden. 我们买了一座带花园的房子。/ China is a very large country with a long history. 中国是一个具有历史悠久的大国。3.(表方式、手段或工具)以,用:He caught the ball with his left hand. 他用左手接球。/ She wrote the letter with a pencil. 她用铅笔写那封信。4.(表材料或内容)以,用:Fill the glass with wine. 把杯子装满酒。/ The road is paved with stones. 这条路用石头铺砌。5.(表状态)在…的情况下,…地:He can read French with ease. 他能轻易地读法文。/ I finished my homework though with difficulty. 虽然有困难,我还是做完了功课。6.(表让步)尽管,虽然:With all his money, he is unhappy. 尽管他有钱,他并不快乐。/ With all his efforts, he lost the match. 虽然尽了全力,他还是输了那场比赛。7.(表条件)若是,如果:With your permission, I’ll go. 如蒙你同意我就去。8.(表原因或理由)因为,由于:He is tired with work. 他工作做累了。/ At the news we all jumped with joy. 听到这消息我们都高兴得跳了起来。9.(表时间)当…的时候,在…之后:With that remark, he left. 他说了那话就离开了。/ With daylight I hurried there to see what had happened. 天一亮我就去那儿看发生了什么事。10. (表同时或随同)与…一起,随着:The girl seemed to be growing prettier with each day. 那女孩好像长得一天比一天漂亮。11.(表伴随或附带情况)同时:I slept with the window open. 我开着窗户睡觉。/ Don’t speak with your mouth full. 不要满嘴巴食物说话。12.赞成,同意:I am with you there. 在那点上我同你意见一致。13.由…照看,交…管理,把…放在某处:I left a message for you with your secretary. 我给你留了个信儿交给你的秘书了。/ The keys are with reception. 钥匙放在接待处。14 (表连同或包含)连用,包含:The meal with wine came to £8 each. 那顿饭连酒每人8英镑。/ With preparation and marking a teacher works 12 hours a day. 一位老师连备课带批改作业每天工作12小时。15. (表对象或关系)对,关于,就…而言,对…来说:He is pleased with his new house. 他对他的新房子很满意。/ The teacher was very angry with him. 老师对他很生气。/ It’s the same with us students. 我们学生也是这样。16.(表对立或敌对)跟,以…为对手:The dog was fighting with the cat. 狗在同猫打架。/ He’s always arguing with his brother. 他老是跟他弟弟争论。17.(在祈使句中与副词连用):Away with him! 带他走!/ Off with your clothes! 脱掉衣服!/ Down with your money! 交出钱来! 【用法】1.表示方式、手段或工具等时(=以,用),注意不要受汉语意思的影响而用错搭配,如“用英语”习惯上用in English,而不是with English。2.与某些抽象名词连用时,其作用相当于一个副词:with care=carefully 认真地/ with kindness=kindly 亲切地/ with joy=joyfully 高兴地/ with anger=angrily 生气地/ with sorrow=sorrowfully 悲伤地/ with ease=easily 容易地/ with delight=delightedly 高兴地/ with great fluency =very fluently 很流利地3.表示条件时,根据情况可与虚拟语气连用:With more money I would be able to buy it. 要是钱多一点,我就买得起了。/ With better equipment, we could have finished the job even sooner. 要是设备好些,我们完成这项工作还要快些。4.比较with 和as:两者均可表示“随着”,但前者是介词,后者是连词:He will improve as he grows older. 随着年龄的增长,他会进步的。/ People’s ideas change with the change of the times. 时代变了,人们的观念也会变化。5.介词with和to 均可表示“对”,但各自的搭配不同,注意不要受汉语意思的影响而用错,如在kind, polite, rude, good, married等形容词后通常不接介词with而接to。6.复合结构“with+宾语+宾语补足语”是一个很有用的结构,它在句中主要用作状语,表示伴随、原因、时间、条件、方式等;其中的宾语补足语可以是名词、形容词、副词、现在分词、过去分词、不定式、介词短语等:I went out with the windows open. 我外出时没有关窗户。/ He stood before his teacher with his head down. 他低着头站在老师面前。/ He was lying on the bed with all his clothes on. 他和衣躺在床上。/ He died with his daughter yet a schoolgirl. 他去世时,女儿还是个小学生。/ The old man sat there with a basket beside her. 老人坐在那儿,身边放着一个篮子。/ He fell asleep with the lamp burning. 他没熄灯就睡着了。/ He sat there with his eyes closed. 他闭目坐在那儿。/ I can’t go out with all these clothes to wash. 要洗这些衣服,我无法出去了。这类结构也常用于名词后作定语:The boy with nothing on is her son. 没穿衣服的这个男孩子是她儿子。 (摘自《英语常用词多用途词典》金盾出版社) - 1 -

精神分裂症应该怎么治疗

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