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Noble Metal Coated Single-Walled Carbon Nanotubes for

Noble Metal Coated Single-Walled Carbon Nanotubes for
Noble Metal Coated Single-Walled Carbon Nanotubes for

Noble Metal Coated Single-Walled Carbon Nanotubes for Applications in Surface Enhanced Raman Scattering Imaging and Photothermal Therapy

Xiaojing Wang,?Chao Wang,?Liang Cheng,?Shuit-Tong Lee,?and Zhuang Liu*,?

?Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Institute of Functional Nano&Soft Materials Laboratory (FUNSOM),Soochow University,Suzhou,Jiangsu215123,China

?Center of Super-Diamond and Advanced Films(COSDAF)and Department of Physics and Materials Science,City University of Hong Kong,Hong Kong SAR,China

*Supporting Information

the excitation source,targeted Raman imaging of cancer

nanocomposite(SWNT-Au-PEG-FA)is realized,with images acquired

nonenhanced SWNT Raman probes.Owing to the strong

shell,the SWNTs-Au-PEG-FA nanocomposite also o?ers

work presents a facile approach to synthesize water-soluble

labeling and fast Raman spectroscopic imaging of biological

nanocomposite developed here may thus be an interesting

INTRODUCTION

Carbon nanotubes,especially singe-walled carbon nanotubes (SWNTs),have attracted signi?cant interest in the area of biomedicine,for potential applications in biological detection, drug delivery,phototherapies,and biomedical imaging.1?7 Owing to their unique one-dimensional(1-D)structure, SWNTs exhibit strong resonance Raman scattering due to their sharp electronic density of states at the van Hove singularities.1SWNTs have several distinctive Raman scattering features,including the radial breathing mode(RBM)and tangential mode(G-band),8which are sharp and strong peaks that can be easily distinguished from?uorescence backgrounds and are thus suitable for optical Raman imaging.Raman imaging of SWNTs in live cells was?rst reported by Heller et al.in2005.9Targeted in vivo Raman imaging was already realized by Zavaleta et al.10in2008.SWNTs with di?erent isotope compositions showed shifted G-band peaks11and could be used as di?erent“colors”for Raman imaging under a single laser excitation.7,12Compared with?uorescence dyes,Raman scattering of SWNTs is resistant to quenching and photo-bleaching,1suitable for long-term tracking and labeling.13,14However,although SWNTs likely exhibit the strongest inherent Raman scattering among all“single molecules”(one nanotube can be deemed as a single conjugated molecule),a relatively long spectral acquisition time(0.5?1s)is usually needed at each pixel during Raman spectroscopic imaging,resulting in a rather long imaging time to obtain one Raman image(a few hours for a100×100image).

Surface enhanced Raman scattering(SERS)is able to enhance Raman signals of molecules adsorbed on rough noble metal surfaces or nanoparticles by as high as many orders of magnitude,and it has been widely investigated in the past few decades for applications in single molecule detection and in chemical and biological sensing,as well as biomedical imaging.15?18SERS studies with SWNTs have also gained particular interest.19?23Chen and co-workers made a network of silver nanoparticle-deposited SWNTs,which showed a strong correlation between localized surface plasmon resonance wavelength,particle size and density,laser excitation wave-

Received:January5,2012

Published:April9,2012

length,and degree of Raman enhancement.19To detect every nanotube on surface-grown SWNTs,Li and co-workers developed an chemical deposition method comprised of seed formation and subsequent seeded growth to deposit gold nanoparticles on the surface of SWNTs.20The average SERS enhancement factors of G-band intensity after gold decoration were 6.4,54,and 97upon excitation with laser wavelengths of 442,633,and 785nm,respectively.Utilizing on-substrate SERS of SWNTs (~60times of SERS enhancement),ultrasensitive sensing of biological molecules was achieved by Dai and co-workers.21Besides depositing noble metal nanoparticles on substrate and solid samples of SWNTs for SERS studies,soluble-phase SERS of SWNTs has also been reported by attaching/growing gold nanoparticles on covalently functional-ized SWNTs (e.g.,oxidized SWNTs).22,23However,covalent functionalization could largely destroy the nanotube structure and drastically decrease Raman signals of SWNTs by many orders of magnitude.To develop SWNT-based nanoprobes with ultrastrong Raman signals for fast Raman imaging of biological samples,pristine SWNTs with noncovalent function-alization have to be used to fabricate water-soluble SERS nanocomposites in the solution phase,which unfortunately have not yet been achieved to our best knowledge.

Here,we report an in situ solution phase synthesis method to grow noble metal nanoparticles onto noncovalently function-alized SWNTs (Scheme 1).Single-strand DNA (ssDNA)is employed to functionalize pristine SWNTs,o ?ering negatively charged DNA coated nanotubes,onto which positively charged poly(allylamine hydrochloride)(PAH)is adsorbed by electro-static force.After attaching negatively charged gold seeds to the surface of DNA/PAH coated SWNTs (SWNT-DNA-PAH),a seeded nanocrystal growth is carried out to obtain SWNT-Au and SWNT-Ag nanocomposites,which are further stabilized by the biocompatible PEG coating.The noble metal coated SWNTs gain excellent SERS e ?ects,with the maximal enhancement factor of over 20.After conjugating the SWNT-Au-PEG nanocomposite with a targeting ligand,folic acid (FA),selective cancer cell labeling and fast Raman imaging are realized using SWNT-Au-PEG-FA,which can also serve as an excellent photothermal agent for cancer cell ablation.

RESULTS AND DISCUSSION

SWNT-metal nanocomposites were synthesized in the solution phase using in situ gold seed attachment and seeded growth methods through a layer-by-layer (LBL)self-assembly procedure.Raw SWNTs were ?rst modi ?ed by ssDNA through

noncovalent binding to acquire water solubility.A cationic polymer,PAH,was then used to coat DNA functionalized SWNTs (SWNT-DNA)by electrostatic interaction,o ?ering SWNTs positive charges.No obvious aggregation of nanotubes was noticed during this step after PAH binding (Supporting Information Figure S1).The ζpotential increased from ?23mV for SWNT-DNA to +24mV for SWNT-DNA-PAH (Supporting Information Figure S2),indicating the successful PAH binding on SWNT-DNA.Negatively charged gold seeds grown in aqueous NaOH were then added in large excess and attached to the surface of SWNT-DNA-PAH.After removal of unattached gold seeds,the ζpotential of nanotubes was measured to be ?15.1mV,a remarkable decrease from that of SWNT-DNA-PAH as the result of gold seeds attachment.Small gold seeds attached on the surface of SWNTs then acted as nucleation sites to induce seeded gold/silver growth,after which both SWNT-Au and SWNT-Ag nanocomposites with ?ne structures were synthesized.Lipoic acid modi ?ed PEG (LA-PEG)was then introduced to stabilize the nano-composites,obtaining SWNT-Au-PEG and SWNT-Ag-PEG stable in various physiological solutions including serum (Supporting Information Figure S3).SEM and TEM images (Figure 1a ?c)of the synthesized SWNT-Au-PEG nano-composite at the optimized condition (added with 4mM of gold growth solution)revealed that gold nanoparticles with relatively uniform sizes of about 40?50nm were densely decorated on the SWNT ?surface after seeded growth,while adding lower or higher concentrations of gold growth solutions resulted in much di ?erent structures (Supporting Information Figure S4).Compared to SWNT-Au-PEG,silver nanoparticles in the SWNT-Ag-PEG sample were obviously bigger in size,with diameters of 70?150nm (Figure 1d ?f).The elemental composition determined by energy-dispersive X-ray spectros-copy (EDS)further evidenced the composition of SWNT-metal composites (Figure 1g).UV/vis/NIR spectra of SWNT-DNA and SWNT-metal composites (Figure 1h)displayed the absorption peaks around 440nm for SWNT-Ag-PEG and about 580nm for SWNT-Au-PEG,both of which showed a dramatic increase compared to DNA functionalized SWNTs.It is worth noting that after the growth of gold shells surrounding cylinder SWNTs,a continuous absorption band from the visible to NIR regions appeared for SWNT-Au-PEG (Figure 1h,the red line).The strong surface plasmon resonance NIR absorption contributed by the gold shell on SWNTs could be utilized to enhance Raman scattering of nanotubes by SERS under NIR excitation,and it also could be useful for enhanced photothermal ablation of cancer cells.24?26

We next carefully studied the SERS enhancement factors (EFs)of SWNT-Au-PEG and SWNT-Ag-PEG samples prepared under varied conditions.The digital photos of SWNT-Au-PEG and SWNT-Ag-PEG solutions synthesized by introducing di ?erent concentrations of aged Au/Ag growth solutions (Figure 2a and b)clearly showed the color change as addition of growth solutions.Raman spectra of various SWNT-Au-PEG and SWNT-Ag-PEG nanocomposites at the same nanotube concentration were recorded under two di ?erent laser excitations (633and 785nm)(Figure 2c ?h).As for SWNT-Au-PEG,under both 633nm and 785nm laser excitations,the SERS EFs ?rst rose as the increase of added growth solution concentrations and reached the optimum condition at ~4mM,after which an obvious decrease of EF values was observed by further increasing the concentration of gold growth solution (Figure 2c ?e),likely owing to the

Scheme 1.Schematic Illustration of the Synthetic Procedure of SWNTs-Metal

Nanocomposite

formation of irregular aggregates with large sizes (Supporting Information Figure S4).The maximal SERS EFs at the optimum condition (4mM gold aged growth solution)were ~7.7and ~12.6,under 633and 785nm excitation,respectively.The SERS enhancement of SWNT-Ag-PEG under 633-nm excitation followed the same trend as that of SWNT-Au-PEG,with the maximal EF of 26.5at 5mM of silver growth solution (Figure 2f and h).However,when excited with the 785nm laser,the EFs of SWNT-Ag-PEG were much lower,showing a maximal EF of ~8.7(Figure 2g and h),likely due to the relatively weak plasmonic absorption of Ag nanostructures at longer wavelength.At the optimized preparation conditions for SWNT-Au-PEG and SWNT-Ag-PEG,10nM of SWNTs was coated with 0.38mg/mL of Au and 2.69mg/mL of Ag,respectively,as determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES)measurement.

Under 785nm excitation,both exciting and scattering photons are in the NIR window (700?900nm)with the lowest tissue absorption and auto ?uorescence background,ideal for optical imaging in biological systems.1,12SWNT-Au-PEG exhibits stronger NIR plasmonic absorption and higher SERS EF under 785nm excitation than SWNT-Ag-PEG.Moreover,

compared to silver,gold is more inert in its chemical property and may show relatively better biocompatibility.24,27?29We thus chose SWNT-Au-PEG for our followed biomedical studies.

A standard cell toxicity test was carried out ?rst to determine the cytotoxicity of the as synthesized SWNT-Au-PEG before it was used for further biological experiments.The experimental results revealed no obvious toxic e ?ect of our SWNT-Au-PEG on treated cells at tested concentrations (Supporting Information Figure S5).

To achieve selective labeling of a speci ?c type of cancer cells,folic acid conjugated LA-PEG (LA-PEG-FA)was used to stabilize as-made SWNT-Au,obtaining SWNT-Au-PEG-FA to target the folate receptor (FR),which is widely known to be up-regulated in many types of cancer cells.FR-positive human epidermoid carcinoma KB cells cultured in an FA-free medium and FR-negative HeLa cells cultured in a normal medium were incubated with SWNT-Au-PEG or SWNT-Au-PEG-FA (5nM)for 30min and washed extensively with phosphate bu ?ered saline (PBS)before Raman imaging (Figure 3a ?d).SWNT-PEG and SWNT-PEG-FA (5nM)were used as the control

to

Figure 1.Characterization of SWNT-Au-PEG and SWNT-Ag-PEG nanocomposites.(a ?c)Representative SEM (a)and TEM (b and c)images of the SWNT-Au-PEG nanocomposite.The inset in (b)is a TEM image of DNA modi ?ed SWNTs.(d ?f)Representative SEM (d)and TEM (e and f)images of the SWNT-Ag-PEG nanocomposite.(g)EDS of the SWNT-Au-PEG (red line)and SWNT-Ag-PEG (black line)nanocomposites under the STEM pattern.(h)UV/vis/NIR absorption spectra of SWNT-DNA (10nM),SWNT-Au-PEG,and SWNT-Ag-PEG solutions (1nM by SWNT content).The above characterization data were obtained using selected SWNT-Au-PEG and SWNT-Ag-PEG samples with the optimum SERS e ?ect (Figure 2).

reveal the bene ?t of SERS for SWNT-based cell labeling and Raman imaging (Figure 3e ?h).

Raman imaging of cells was conducted by a Horiba-JY confocal Raman microscope using a 785nm laser as the excitation source.To ensure fast Raman scanning,a rather short integration time (0.1s per pixel)was used in combination with the SWIFT ultrafast Raman mapping model.Under our

imaging condition,strong Raman signals were observed for KB cells incubated with SWNT-Au-PEG-FA,while cells incubated with SWNT-Au-PEG showed much weaker signals,suggesting selective binding of SWNT-Au-PEG-FA on FR positive cancer cells,which was also evidenced by TEM images of cell samples (Supporting Information Figure S6).As expected,no obvious Raman signals were noted from

HeLa

Figure 2.Studies on the SERS e ?ects.(a and b)Photos of SWNT-Au-PEG (a)and SWNT-Ag-PEG (b)solutions prepared by adding di ?erent concentrations of aged growth solutions.From left to right were samples added with increasing concentrations of growth solutions (0mM to 7mM).All the samples were diluted 5times by DI water before photos were taken.(c and d)Raman spectra of SWNT-Au-PEG prepared by adding di ?erent concentrations of growth solutions taken under 633nm (c)and 785nm (d)laser excitation.(f and g)Raman spectra of SWNT-Ag-PEG samples prepared by adding di ?erent concentrations of silver growth solutions taken under 633nm (f)and 785nm (g)laser excitation.(e and h)SERS EFs of SWNT-Au-PEG (e)and SWNT-Ag-PEG (h)samples with increasing concentrations of growth solutions.Error bars were based on three parallel measurements for each sample.

cells after incubation with either SWNTs-Au-PEG or SWNTs-Au-PEG-FA.In marked contrast,KB cells labeled with SWNT-PEG-FA showed neglectable Raman signals at our experimental conditions (0.1s integration time per pixel),due to the relatively low Raman intensity of nanotubes without SERS.As semiquanti ?cation,all Raman spectra in each Raman spectroscopic image were integrated (Figure 3j),showing excellent labeling speci ?city of SWNT-Au-PEG-FA and dramatically increased Raman labeling performance of Au coated SWNTs as compared to plain SWNTs without SERS.The key bene ?t of using Au decorated SWNTs as Raman probes for cell imaging is the short imaging time owing to the strongly enhanced Raman signals by SERS.The time taken to acquire one Raman image could be as short as a few minutes in this work,a remarkable decrease from the few hours needed in previous SWNT-based Raman imaging of cells (1?2s integration time at each pixel).In another control experiment,we compared Raman images of SWNT-Au-PEG-FA labeled KB

cells and SWNT-PEG-FA labeled cells (Supporting Informa-tion Figure S7).While a 0.1s integration time (~6min for one 50×50image)was enough to obtain su ?cient Raman signals using SWNT-Au-PEG-FA as the Raman probe,a long integration time of 1s at each pixel (~1h for one 50×50image)is necessary to collect su ?cient signals for a decent Raman spectroscopic image of cells labeled with unmodi ?ed SWNT-PEG-FA (Supporting Information Figure S7).The absolute signals in the latter image were still slightly weaker than the former,despite the 10×imaging time used.

Both carbon nanotubes and gold nanomaterials with strong light absorbing capabilities have been widely explored in the photothermal therapy (PTT)of cancer.3,25,26,30,31The growth of the gold shell dramatically increased the optical absorbance of the SWNT-based nanocomposite in the NIR region.We thus explored the enhanced photothermal ablation of cancer cells with our SWNT-Au-PEG nanocomposites.When exposed to an 808nm NIR laser at a power density of 1W/cm 2,

the

Figure 3.Raman imaging of cells.(a ?h)Raman images of SWNT-Au-PEG-FA (a and b),SWNT-Au-PEG (c and d),SWNT-PEG-FA (e and f),and SWNT-PEG (g and h)labeled KB (a,c,e,g)and HeLa (b,d,f,h)cells.The nanotube concentrations in all samples were kept constant at 5nM.(i)High-resolution Raman image of a SWNTs-Au-PEG-FA labeled KB cell.The insets in parts a ?i corresponded to bright ?eld images of cells.(j)Averaged Raman spectra in each image from (a)to (h).The step size was 8μm in images (a ?h)and 1.5μm in (i).The intensity of the SWNT Raman G-band peak at 1590cm ?1was used to contrast the above Raman spectroscopic images.

SWNT-Au-PEG solution (1nM by SWNT content)showed a nearly 30°C of temperature rise within 5min.In contrast,the temperature change of the SWNT-PEG solution (5nM)was much less signi ?cant under the same laser irradiation conditions.

For targeted cancer cell ablation,KB cells were incubated with SWNT-Au-PEG-FA,SWNT-Au-PEG,SWNT-PEG-FA,and SWNT-PEG,respectively,at the same nanotube concentration.After laser irradiation of 808nm for 5min at the power density of 1W/cm 2,relatively cell viabilities were determined (Figure 4b).The majority of KB cells treated with SWNT-Au-PEG-FA were killed after laser irradiation,while SWNT-Au-PEG treated cells showed much less cell death after exposure to the NIR laser.In contrast,either SWNT-PEG-FA or SWNT-PEG treated cells showed negligible cell death after laser irradiation.Bright ?eld microscopy images of trypan blue stained cells and confocal ?uorescence microscopy images of Calcein AM/Propidium iodide (PI)costained cells after various treatments (Figure 4c ?j)provided the same information.

These results clearly demonstrate that the SWNT-Au nano-composite has much better photothermal therapeutic e ?ect than plain SWNTs.Control experiments on FR negative HeLa cells uncovered no appreciable cell death after SWNT-Au-PEG-FA incubation and laser irradiation,further evidencing that the photothermal ablation of cancer cells was highly selective (Supporting Information Figure S8).

To demonstrate the advantage of our SWNT-Au nano-composite over gold nanostructures used in PTT,we compared its photostability with gold nanorods (AuNRs,length =41?45nm,width =11?13nm).After 808-nm laser irradiation for 60min at 1W/cm 2,PEGylated AuNRs (AuNR-PEG)solution lost the majority of its absorbance at 808nm,while the SWNT-Au-PEG solution merely decreased to 87%of its initial absorbance (Figure 5a ?c).The color of AuNR-PEG changed from dark pink to nearly colorless,while the color of SWNT-Au-PEG showed no apparent change (Figure 5d).The decrease in the absorbance of AuNRs under laser irradiation is a problem in AuNR-based PTT applications,and owing to the

morphology

Figure 4.Targeted photothermal ablation of cancer cells.(a)The heating curves of water and the SWNT-PEG (5nM)and SWNT-Au-PEG

nanocomposites (1nM by SWNT)under 808nm laser irradiation at a power density of 1W/cm 2.(b)Relative cell viabilities of SWNT-Au-PEG-FA,SWNT-Au-PEG,SWNT-PEG-FA,and SWNT-PEG treated KB cells with or without laser irradiation (808nm,1W/cm 2,5min).(c ?f)Optical microscopy images of trypan blue stained KB cells after being incubated with SWNT-PEG (c),SWNT-PEG-FA (d),SWNT-Au-PEG (e),or SWNT-Au-PEG-FA (f),and then exposed to the laser irradiation.The nanotube concentration was 5nM in all above samples.(g ?j)Confocal ?uorescence images of calcein AM (green,live cells)/propidium iodide (red,dead cells)costained KB cells bearing the same PTT treatment as that in parts c ?f.

change (melting)of nanorods under local heating (Supporting Information Figure S9).32,33With a nanotube as the backbone,the SWNT-Au nanostructure,which also looks like a “nanorod ”,may be more resistant to melting under photo-induced local heating.

CONCLUSIONS

In summary,an in situ synthetic method has been developed to decorate noble metal nanoparticles onto noncovalently functionalized SWNTs with high density in the solution phase,obtaining SWNT-Au-PEG and SWNT-Ag-PEG nano-composites which exhibit excellent concentration and excita-tion-source dependent SERS e ?ects.Utilizing FA conjugated SWNT-Au-PEG-FA,selective cancer cell labeling and Raman imaging is realized,with remarkably shortened imaging time compared to that of using a nonenhanced SWNT-nanoprobe,owing to the strongly enhanced Raman signals of nanotubes by SERS.Moreover,the SWNT-Au-PEG-FA nanocomposite also exhibits dramatically improved photothermal cancer cell killing e ?cacy due to the strong surface plasmon resonance absorption contributed by the gold shell grown on the nanotube surface.The photothermal stability of SWNT-Au-PEG is found to be signi ?cantly higher than that of https://www.doczj.com/doc/1c11036512.html,bining the intrinsic properties of both SWNTs and gold,the SWNT-Au nanocomposite developed here may be an interesting nanoplatform promising in biosensing,optical imaging,and phototherapy.

EXPERIMENTAL SECTION

Seed-Mediated Ag/Au Growth on SWNTs.Noncovalent Coating of Charged Polymers on SWNTs.Noncovalent function-alization of SWNTs with DNA has been well established in

earlier reports.34?37A DNA solution with the sequence of 5′-ATTCGCGAGTCGCGA-3′(Sangon Biotech)at a concen-tration of 20μM was sonicated with raw Hipco SWNTs (0.15mg/mL)for 1h.The SWNT-DNA suspension was then centrifuged at 14000rpm for 1h to remove aggregates.Excess DNA in the supernatant was then removed by ?ltration through 100kDa ultracentifugal ?lter devices (Millipore Amicon Ultra).DNA coated SWNTs with negative charges were then modi ?ed by poly(allylamine hydrochloride)(PAH,purchased form Sigma Inc.).One milliliter of PAH (10mg/mL)was added to 5mL of 200nM SWNT-DNA (calculated by the extinction coe ?cient at 808nm:ε808nm =7.9×106M/cm)38under rigorous stirring.After continued stirring over-night,the mixture was brie ?y sonicated for a few seconds to obtain a homogeneous solution,which was then thoroughly washed with deionized (DI)water by ?ltration through 100-nm ?lter membrane (Millipore)to remove excess PAH.

Attachment of Gold Seeds on SWNTs.Negatively charged gold seeds were synthesized following a reported protocol 39by reduction of hydrogen tetrachloroaurate (III)hydrate (HAuCl 4)with tetrakis-(hydroxymethyl)phosphonium chloride (THPC)in a solution of NaOH.SWNT-DNA-PAH was attached with gold seeds by mixing 2mL of 200nM SWNT-DNA-PAH with 20mL of gold seeds solution.After stirring at room temperature for 4h,excess unattached gold seeds were removed by centrifugation at 14800rpm with supernatants discard,and washed with DI water for 2?3times.

Preparation of Growth Solutions.An aged gold growth solution was prepared by mixing 2mL of 25mg/mL potassium carbonate (K 2CO 3)with 4mL of 1wt %HAuCl 4in 200mL of DI water.The color of the mixture changed from yellow to colorless within 30min.Silver growth solution was prepared using an analogous procedure (added 2mL of 1wt %AgNO 3instead of HAuCl 4·H 2O).The solution was aged for 1day before use.40

Seed Mediated Au/Ag Growth on SWNTs.SWNT-Au and SWNT-Ag nanocomposites were then synthesized by a seeded

growth

Figure https://www.doczj.com/doc/1c11036512.html,parison of photostability between SWNT-Au-PEG and AuNR-PEG under 808-nm laser irradiation.(a and b)UV/vis/NIR absorption spectra of AuNR-PEG (a)and SWNT-Au-PEG (b)solutions before and after laser irradiation (1W/cm 2for 1h).(c)Change of relative absorbance at 808nm for SWNT-Au-PEG and AuNR-PEG solutions under laser exposure at di ?erent power densities (0.2?1W/cm 2).(d)Photos of SWNT-Au-PEG and AuNR-PEG solutions before irradiation (B.I.)and after the laser irradiation (A.I.)at 1W/cm 2for 1h.

procedure,with small gold seeds attached on the surface of SWNTs as nucleation centers.To grow gold nanoparticles onto SWNTs,200μL of gold seeds attached SWNTs(50nM)was added with varying amounts of aged gold growth solution(1.7?11.9mL).After stirring the mixture for10min,various volumes of formaldehyde(37%,8.5?59.5μL)were added as the reducing agent.The solution color changed from colorless to pink and then purple during the reaction. SWNT-Ag nanocomposite was prepared in the same manner,but with a mixture of formaldehyde and ammonium hydroxide(25?175μL)as the reducing agent.For the control samples,DI water was added instead of aged Au/Ag growth solutions.

PEGylation of SWNT?Metal Nanocomposites.Lipoic acid modi?ed PEG(LA-PEG)and folic acid conjugated LA-PEG(LA-PEG-FA)were synthesized following a reported protocol41and used to stabilize as-made SWNT-Ag and SWNT-Au nanocomposites.To1 mL of SWNT-Ag or SWNT-Au solution,5mg of LA-PEG or LA-PEG-FA was added at~20min after the Ag/Au nanoparticle growth was initiated(by adding reducing agents).Excess reagents were removed by centrifugation at14800rpm and repeated water washing. For biological experiments,SWNT-Au-PEG and SWNT-Au-PEG-FA were further dialyzed against DI water using3500Da MWCO membranes to remove residual ions.

Synthesis of SWNT-PEG and SWNT-PEG-FA.PEG-grafted poly(maleic anhydride-alt-1-octadecene)(PMHC18-mPEG)and the one with folic acid modi?cation(PMHC18-mPEG-FA)was synthe-sized following our previously reported protocols.3,42,43SWNT-PEG and SWNT-PEG-FA were synthesized by sonicating raw SWNTs(0.2 mg/mL)in aqueous solutions of PMHC18-mPEG or PMHC18-mPEG-FA(3mg/mL),respectively,for1h.The PEGylated SWNT suspensions were then centrifuged at14000rpm for1h to remove aggregates.The supernatants were thoroughly washed with DI water by?ltration through a100nm?lter membrane(Millipore)to remove excess polymers.

Synthesis of AuNR-PEG.AuNRs were synthesized following a well established protocol in a solution of cetyl-trimethylammonium bromide(CTAB).44After removal of excess CTAB from as-made AuNRs by centrifugation and water washing,LA-PEG(5mg/mL)was added to stabilize AuNRs.After stirring for4?6h,the remaining CTAB,which fell down from Au nanorods by ligand exchange as well as excess LA-PEG,was also removed by centrifugation. Characterizations.Scanning electron microscopy(SEM)images were taken by using a FEI Quanta200F scanning electron microscope. Transmission electron microscopy(TEM)images were obtained using a Philips CM300transmission electron microscope operating at an acceleration voltage of200kV.All TEM samples were deposited on 300mesh holey carbon-coated copper grids and dried overnight before examination.UV/vis spectra were obtained with a PerkinElmer Lambda750UV/vis spectrophotometer over the wavelength range 200?1000nm.Raman spectra were taken using a Raman spectrometer (Horiba LabRam HR800)for SWNT samples in the solution phase loaded in capillary tubes,with the laser beam focused on the center of a tube in both the longitude and transverse directions.

Raman Imaging of Cells.All cell culture-related agents were purchased from Invitrogen.Human carcinoma KB cells and HeLa cells obtained from the American Type Culture Collection(ATCC)were cultured in folate acid free RPMI-1640and completed high-glucose DMEM cell medium,respectively,both supplemented with10%fetal bovine serum(FBS)and1%penicillin/streptomycin.For Raman imaging,200μL of KB or Hela cells were incubated with SWNT-PEG, SWNT-PEG-FA,SWNT-Au-PEG,and SWNT-Au-PEG-FA solutions for0.5h at4°C.The?nal concentrations in these incubation solutions were all5nM in term of nanotube concentration.After washing with phosphate bu?ered saline(PBS)for three times,cells were?xed by2.5%glutaraldehyde and imaged under a Raman confocal microscope(Horiba LabRam HR800)with a785nm laser(80mW) as the excitation light source.A drop of cell suspension(about10?20μL)was sealed between two thin quartz cover-slides for imaging.A 50×objective lens(~1μm laser spot size)was used,and the pinhole was selected as400μm.Each Raman spectroscopic map(Figure3a?i) contains at least50×50spectra,with0.1s integration time for each spectrum.Step sizes of8μm and1.5μm were used for Raman mapping to obtain large area images(Figure3a?h)and high resolution images(Figure3i),respectively.

Selective Photothermal Ablation of Cancer Cells.For photothermal therapy,KB cells were precultured in96-well cell culture plates at1×104/well for24h and then added with SWNT-PEG,SWNT-PEG-FA,SWNT-Au-PEG,or SWNT-Au-PEG-FA at the tested concentration(5nM).After incubation for0.5h at4°C,cells were washed with PBS to remove excess nanomaterials and then incubated at37°C for another2h to allow the internalization of nanotubes.An808nm NIR laser was used to irradiate cells at a power density of1W/cm2for5min.The standard cell viability assay using3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT, Sigma Inc.)was carried out to determine the cell viabilities relative to the control cells incubated with the same volume of PBS.For trypan blue staining,KB cells(2×105cells)grown in the FBS containing medium cultured in35mm culture dishes were irradiated by the808 nm laser after incubation with SWNT-PEG,SWNT-PEG-FA,SWNT-Au-PEG,or SWNT-Au-PEG-FA,washed with PBS,and stained with 0.04%Trypan blue solution(Sigma Inc.)for5min.Microscopic

images of cells were then taken using a Leica microscope.■ASSOCIATED CONTENT

*Supporting Information

Zeta potential measurement during the synthesis procedure, characterization of SWNT-DNA-PAH,photos of SWNT-Au-PEG and SWNT-Ag-PEG in various physiological solutions,in vitro cellular toxicity assay of SWNT-Au-PEG,TEM images of cell samples,Raman imaging of KB cells incubated with SWNT-Au-PEG-FA and SWNT-PEG-FA,and TEM images of AuNR-PEG before and after laser irradiation.This material is

available free of charge via the Internet at https://www.doczj.com/doc/1c11036512.html,.■AUTHOR INFORMATION

Corresponding Author

zliu@https://www.doczj.com/doc/1c11036512.html,

Notes

The authors declare no competing?nancial interest.■ACKNOWLEDGMENTS

(This work was supported by the National Basic Research Program(973Program)of China(2012CB932601, 2011CB911002),the National Natural Science Foundation of China(51072126,51002100,51132006),the Research Grants Council of Hong Kong SAR-CRF Grant(CityU5/CRF/08), and a Project Funded by the Priority Academic Program

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CA6140车床拨叉831006.

目录 一、零件的分析 (2) (一)零件的作用 (2) (二)零件的工艺分析 (2) 二.工艺规程设计 (2) 1,确定生产类型 (2) 2,确定毛坯的制造形式 (2) 3,基面的选择 (2) 4,制定工艺路线 (3) 三.夹具设计 (12) (一)问题的提出 (12) (二)夹具设计 (12)

一、零件的分析 (一)零件的作用 题目所给的零件是CA6140车床的拨叉。它位于车床变速机构中,主要起换档,使主轴回转运动按照工作者的要求工作,获得所需的速度和扭矩的作用。零件上方的φ22孔与操纵机构相连,二下方的φ55半孔则是用于与所控制齿轮所在的轴接触。通过上方的力拨动下方的齿轮变速。两件零件铸为一体,加工时分开。 (二)零件的工艺分析 零件的材料为HT200,灰铸铁生产工艺简单,铸造性能优良,但塑性较差、脆性高,不适合磨削,为此以下是拨叉需要加工的表面以及加工表面之间的位置要求: 1小头孔以及与此孔相通的的锥孔、螺纹孔 2大头半圆孔Ф55 3小头孔端面、大头半圆孔上下Ф73端面,大头半圆孔两端面与小头孔中心线的垂直度误差为0.07mm,小头孔上端面与其中心线的垂直度误差为0.05mm。 由上面分析可知,可以粗加小头孔端面,然后以此作为粗基准采用专用夹具进行加工,并且保证位置精度要求。再根据各加工方法的经济精度及机床所能达到的位置精度,并且此拨叉零件没有复杂的加工曲面,所以根据上述技术要求采用常规的加工工艺均可保证。 二.工艺规程设计 1,确定生产类型 已知此拨叉零件的生产类型为中批量生产,所以初步确定工艺安排为:加工过程划分阶段;工序适当集中;加工设备以通用设备为主,大量采用专用工装。 2,确定毛坯的制造形式 确定毛坯种类:零件材料为HT200。考虑零件在机床运行过程中所受冲击不大,零件结构又比较简单,生产类型为中批生产,故选择铸件毛坯。查《机械制造工艺及设备设计指导手册》(后称《指导手册》)选用铸件尺寸公差等级CT9级。 3,基面的选择 定位基准是影响拨叉零件加工精度的关键因素。基准选择得合理可以使加工质量得到保证,生产率得以提高。否则,加工过程中将问题百出,更有甚者,造成零件的大批报废,使生产无法正常进行。 (1)粗基准的选择对于零件而言,尽可能选择不加工表面为粗基准。而对有若干个不加工表面的工件,则应以与加工表面要求相对位置精度较高的不加工表面作粗基准。根据这个基准选择原则,现选取φ40的外表面和底面为粗基准加工φ22孔的上表面。 (2)精基准的选择主要应该考虑基准重合的问题。因此选择精加工过的φ55mm孔为精基准,限制四个自由度。 考虑要保证零件的加工精度和装夹准确方便,依据“基准重合”原则和“基准统一”原则,以粗加工后的上表面和镗过的孔为主要的定位精基准。

常用法兰规格尺寸表

常用法兰规格尺寸表(国标) 发布时间:2010.07.13 新闻来源:法兰-法兰盘-法兰毛坯-弯头-三通-无缝钢管-聊城荣丰法兰制造厂浏览次数: 593 常用法兰规格尺寸表(国标) GB9119,2—88GB9119,2—88 in 法兰公称 通径 10kg=1.0MPa 公称通径 16kg=1.6MPa 法兰外 径 螺栓孔 距 螺栓直 径 螺栓孔数法兰厚度法兰外径螺栓孔距螺栓直径螺栓孔数法兰厚度 3/8 DN10 50 60 14 4 14 DN10 90 60 14 4 14 1/2 DN15 59 65 14 4 14 DN15 95 65 14 4 14 3/4 DN20 105 75 14 4 16 DN20 105 75 14 4 16 1 DN25 115 85 14 4 16 DN25 115 85 14 4 16 11/4DN32 140 100 18 4 18 DN32 140 100 18 4 18 11/2DN40 150 110 18 4 18 DN40 150 110 18 4 18 2 DN50 165 125 18 4 20 DN50 165 125 18 4 20 21/2DN65 185 145 18 4 20 DN65 185 145 18 4 20 3 DN80 200 160 18 8 20 DN80 200 160 18 8 20 31/2DN100 220 180 18 8 22 DN100 220 180 18 8 22 4 DN12 5 250 210 18 8 22 DN125 250 210 18 8 22 5 DN150 285 240 22 8 24 DN150 285 240 22 8 24 6 DN200 340 295 22 8 24 DN200 340 295 22 8 26 8 DN250 395 350 22 12 26 DN250 405 355 26 12 29 10 DN300 445 400 22 12 28 DN300 460 410 26 12 32 12 DN350 505 460 22 16 30 DN350 520 470 26 16 35 14 DN400 565 515 26 16 32 DN400 580 525 30 16 38 16 DN450 615 565 26 20 35 DN450 640 585 30 20 42 18 DN500 670 620 26 20 38 DN500 715 650 33 20 46 20 DN600 780 725 26 20 42 DN600 840 770 36 20 52

智能变电站通信网络技术方案

智能变电站通信网络技术方案 1 智能变电站通信网络总体结构 智能变电站通信网络采用IEC 61850国际标准,IEC 61850标准将变电站在结构上划分为变电站层、间隔层和过程层,并通过分层、分布、开放式网络系统实现连接。 变电站层与间隔层之间的网络称为变电站层网络,间隔层与过程层之间的网络称为过程层网络。 变电站层网络和过程层网络承载的业务功能截然不同。为了保证过程层网络的实时性、安全性,在现有的技术条件下,变电站层网络应与过程层网络物理分开,并采用100M及以上高速以太网构建。 通讯在线保护及故障系统服务器系统服务器GOOSE视频监视终端信息管理兼操作员站2兼操作员站1远动远动联动服务器子站工作站1工作站2变电站层 MMS/GOOSE网变电站层网络 超五类屏蔽 双绞线 其他智能电能保护故障间隔层设备计量测控录波 SMV网光缆过程层网络GOOSE网 合并智能单元单元过程层 光缆电缆

电子式开关设备 互感器(主变、断路器、刀闸) 智能变电站通信网络基本构架示意图 2 变电站层网络技术方案 功能: 变电站层网络功能和结构与传统变电站的计算机监控系统网络基本类似,全站信息的汇总功能(包括防误闭锁)可依靠MMS/GOOSE网络实现。 拓扑结构选择: 环形和星形拓扑结构相比,其网络可用率有所提高(单故障时两者均不损失功能,少数的复故障环形网可以保留更多的设备通信),但是支持环网的交换机和普通星型交换机相比价格大大提高。 国内经过多年的技术积累,装置普遍具备2~3个独立以太网口, 星型网络在变电站实际应用有着更加丰富的使用经验。 国内220kV及以上变电站层网络一般采用双星型拓扑结构;110kV及以下变电站层网络一般采用单星型拓扑结构。 变电站层双星型网络结构示意图 系统服务器兼操作员站远动工作站变电站层 变电站层网络变电站层交换机2 变电站层交换机1

网络办公自动化

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智能电力通信网管控系统研究 发表时间:2016-08-29T09:45:02.633Z 来源:《电力设备》2016年第12期作者:马静勇 [导读] 职能电力通信网是电网安全稳定运行的重要支撑,它是一个技术集中、通信设备品种众多的异构型网络。 马静勇 (广东电网有限责任公司东莞供电局广东东莞 523000) 摘要:电力通信网主要作用是保证电力系统安全稳定运行,是电力系统的重要基础设施,能够提高通信资源的有序化、规范化管理水平。因此,对通信设备及通信业务进行集中化、智能化监控,对通信运维工作进行闭环化、流程化管理,形成智能化、综合化、自动化的电力通信网智能管控网络,是提高工作效率,保障通信设备安全运行的有效手段。本文对智能电力通信网管控系统构架、管控系统的功能、应用软件功能构架等进行了详细的分析,提出了基于Web层次化的智能电力通信网管系统体系结构。 关键词:智能化;电力通信网;管控系统;基于Web层次化; 职能电力通信网是电网安全稳定运行的重要支撑,它是一个技术集中、通信设备品种众多的异构型网络。随着电力通信网络规模的不断扩大,以及通信在电网生产中重要性地位的不断提高,如何进一步改善电力通信运行管理水平和服务质量,是电力通信系统面临的难点问题之一。解决这一问题的关键,是建立一个智能通信网管控制系统来进行整个通信网络资源和业务的综合管控。 1.通信综合网管系统 TMN是 ITU-T 提出来的关于网络管理系统化的解决方案,是网管领域的热门话题。TMN的基本概念是提供了一个有组织的网络结构,以取得各种类型的操作系统之间以及操作系统与电信设备之间的互联。它是一个完整的独立的管理网络,是各种不同应用的管理系统按照TMN 标准接口互联而成的网络。电力通信网综合网管系统采用 TMN 功能体系结构来设计,在逻辑分层上采用国际流行的四层模式,各功能层与网管的功能模块的关系参见图1-1。下面对 TMN 功能体系的逻辑分层和管理功能进行简要介绍。 图1-1 网管功能与模块的关系 当使用 TMN 体系结构为电信业务活动提供管理能力时,必须根据不同的管理重点和要求,将管理环境按专业特点分成多个层次,每个层次具有不同的管理目标和技术需求。TMN 的逻辑分层体系结构如下:网元管理层、网络管理层、服务管理层、业务管理层。网元管理层(EML)在单个或分组的基础上管理每个网元,并且支持对网元所提供功能的抽象化。网元管理是网管系统的基础,它负责向上级的网络管理层提供不依赖于厂商的网元描述。这一层主要是面向设备、单条电路。包括:数据接入、数据采集系统。其直接的结果是实现对设备的监测、维护、管理,同时提供数据转换接入功能支持上层管理系统。 网络管理层(NML)在网元管理层(EML)的支持下负责网络的管理。负责提出一种网络资源和功能相对独立的技术观点,以便服务于管理层。 服务管理层(SML)也叫业务管理层,涉及并负责服务的合同方面,这些服务正在向客户提供,或者适合向潜在的新客户提供。服务管理层中的一些主要功能是业务申请处理、申告处理和开列清单。 事务管理层(BML)与最高管理部门的所有决策有关。该层涉及整个网络及其管理系统的专有权。为防止对其功能性的访问,B-OSF (事务管理层运行系统功能)一般不支持 x参考点。 2.智能通信网管控系统结构 智能通信网管控系统的总体架构蓝图参考了TMF的eTOM和ITU-T的TMN中的相关描述,总体功能架构如图2-1所示,其核心功能平面是质量与维护管理和资源与网络管理两个横向的管理视图,它与网络运行分析、综合呈现门户两个平面共同构成立体的管理功能框架,各平面的各个功能组件共同构成立体化的体系架构模型。 智能通信网管控系统的功能域分为四大功能组: 质量与维护管理功能组:其主要功能包括业务保障和运维管理; 资源与网络管理功能组:其主要功能包括网络资源管理、综合网络管理应用环境和专业网管(NMS、EMS)等; 网络运行分析功能组:其主要功能包括数据公共管理、数据质量管理、数据共享管理、数据整合管理、数据应用管理;综合呈现门户功能组:其主要功能包括统一认证和单点登录、综合展示等。

CA6140车床拨叉831002说明书三

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法兰盘规格尺寸

HG/T 20592 40-16 RF A=M20*1.5: 40-16是公称直径DN40的法兰,公称压力16公斤也就是1.6MPa,RF指密封面为突面,A=M20X1.5指该法兰上所配的螺栓规格。 GB9119,2—88GB9119,2—88 in 公称 通径 10kg=1.0MPa 公称 通径 16kg=1.6MPa 法 兰 外 径 螺栓 孔距 螺 栓 直 径 螺栓 孔数 法兰 厚度 法兰 外径 螺栓 孔距 螺栓 直径 螺栓 孔数 法兰厚度 3/8 DN10 506014414DN10 906014414 1/2 DN15 596514414DN15 956514414 3/4 DN20 1057514416DN20 1057514416 1 DN25 1158514416DN25 1158514416 11/4DN32 14010018418DN32 14010018418 11/2DN40 150********DN40 150******** 2 DN50 16512518420DN50 16512518420 21/2DN65 185********DN65 185******** 3 DN80 20016018820DN80 20016018820 31/2DN10 22018018822DN100 22018018822 4 DN12 5 25021018822DN125 25021018822 5 DN15 28524022824DN150 28524022824 6 DN20 34029522824DN200 34029522826 8 DN25 395350221226DN250 405355261229 10 DN30 445400221228DN300 460410261232 12 DN35 505460221630DN350 520470261635

网络办公自动化系统成功运行

经济欠发达地区如何在世界信息化潮流和知识经济时代到来时抓住机遇进行信息化的建设、普及?如何实现现代社会的信息化?经过长期的实践证明,单靠传统的发展模式已经不能实现整个社会的信息化,缩小与经济发达地区的信息化差距存在巨大的困难。要发展要创新,关键在思想观念和技术、设备、资源配置上,要有超常规的发展方式才能实现信息化的普及。经济欠发达地区要有“结合实际,注重实效,稳步发展”的信息技术教育发展思路,坚持“边规划边建设、边培训边应用”的原则,做到“创造条件上设备,精心管理抓使用,潜心研究促效益”,还要与“建网、建库、建队”同时抓。只有这样信息化建设才会有长足的发展。 一、要搞好信息化建设、普及 由于多方面的原因,世界贫困人口多,信息化建设落后,观念陈旧、经费匮乏、师资紧缺是制约经济欠发达地区信息化建设的三大瓶颈。要因地制宜建设好现代远程教育网络和国际互联网。特别是加快现代远程教育网络的发展,加大投入,做好设备、资源、人才培养等。 搞好信息化建设、普及,要有自力更生的思想,积极调动当地人才超前发展,发扬奉献精神,大家齐心出资才能把设备、资源、人才问题解决,早日步入信息化的快车道。只有这样,经济欠发达地区才能与发达地区享有共同发展的机遇。 二、经济欠发达地区要做好人才的培养、设备配置、资源建设 人才培养首当其冲,可采取走出去请进来和校本学习的办法。派有信息素养的人到外地去学习、考察发达地区建设情况。回来以后要做三件事:一是书面向领导汇报考察的情况;二是广泛宣传外地建设经验,以实现资源共享,让没有出去的人也了解外面的信息;三是自己带头发展。举办信息化建设论谈,交流信息化建设与普及的问题。 如果有了人才,而没有设备,就像有鱼无水。从一定意义上说,信息化环境构建是一项花费钱财的工程。欠发达地区本来就资金困难,无米之炊不行,等米下锅耽误了信息化的普及更不行。要根据自身实际制定利用信息技术设备的总体规划和实施细则。规划不要贪大求洋,但要具有前瞻性、标准性和实用性,体现“高起点、远打算、近着眼、有重点”的发展信息化建设。在实施中,要根据“少花钱,多办事,用好钱,办大事”的原则,分期分批,逐步到位。

电力通信资源管理系统的及应用

113 目前,在通信网络规划、建设、维护中,资料数据都以竣工资料、工程图纸等纸介质或独立的计算机存储文件方式保存。新并网设备及新电路的开通、运行电路的调整、故障抢修、报表统计分析仍旧依靠传统的手工方式完成,使得工作效率低下、管理标准不统一、数据准确性差。现在的管理方式已不能适应当前发展的需求。建立一个统一平台,实现对汕头供电局通信资源的管理尤为重要。系统的建成将直接影响到通信网络的高效运行维护,通信资源的准确、快速调度,并为通信网络规划建设提供参考依据。因此,系统的建设应关注整个通信网中的物理资源、逻辑资源以及业务资源,着重应用于通信网的运行维护管理,服务于电网的生产与企业 的经营,兼顾通信网的规划设计和工程的建设。 1 通信资源管理系统的结构 通信资源管理系统由硬件结构、软件基础架构及软件功能模块共同构成。 1.1 系统硬件网络结构 汕头供电局通信网资源系统的硬件支撑平台主要应由相应的网络设备、主机系统、终端设备及安全设备组成。硬件平台架构如图1所示: 通过配置一台数据库服务器、一台应用服务器、一台TMIS(通信管理信息系统)服务器以及多个管理客户端,通过交换机组建成一个专用的网络,客户端工作站通过访问应用服务器,实现对电 力通信资源的维护和管理。再配置两台数据采集服务器,通过接口适配器与网管系统连接,实时采集 网管系统的数据并及时更新到后台数据库中。 图1 硬件架构图 1.2 系统软件体系结构 在电力通信资源管理平台中,采取基于J2EE的三层体系结构。整个系统分为三层:数据存储层、逻辑处理层和界面层。图2给出了系统的总体体系 结构模型: 图2 通信资源管理系统软件体系结构图1.2.1 数据存储层主要存放资源管理系统中涉及的所有数据以及数据间的信息关系,同时还保存了系统运行和管理所需要的一些数据,包括用户 电力通信资源管理系统的研究及应用 张伟亮 (广东电网公司汕头供电局,广东 汕头 515041) 摘要: 为了提高电力通信网络运行维护高效性,保证通信资源的准确及快速调度,并为通信网络规划建设提供参考依据,汕头供电局建设了通信资源管理系统。系统对通信网中的物理资源、逻辑资源以及业务资源进行了管理。文章从系统的结构、系统规划建设、资源数据的清查录入等方面进行阐述并对如何保证系统的生命力提出了建议。 关键词: 电力通信;资源管理;系统建设;物理资源;逻辑资源;业务资源中图分类号: TN915 文献标识码:A 文章编号:1009-2374(2012)28-0113-032012年第28期(总第235期)NO.28.2012 (CumulativetyNO.235)

网络办公自动化系统

******学院毕业论文 (计算机网络专业) 网络办公自动化系统 申请人姓名 学科专业计算机网络 指导教师 二〇〇五年六月

摘要 本系统是根据中小企业日常办公的实际需要,而专门开发的网络办公信息平台。此次毕业设计通过对B/S模式、ASP开发工具、数据库以及SQL语言的深入学习及实践,主要完成了网络办公自动化系统的需求分析、数据库设计、应用程序设计的工作。 首先,在绪论部分,根据市场的需求分析引出我们做这个课题的目的,以及我们这个课题的简要概况。 第二章介绍了办公自动化系统的定义、发展背景以具体的OA系统的实现模式,并分析了当前OA系统存在的问题,由此引出的本系统的解决方案。 第三章从系统功能、目标入手,对整个系统进行了需求分析、功能模块划分,阐述了系统平台的选择,介绍了开发工具ASP、Dreamweave,然后介绍了关系型数据库的基本概念,并对数据字典进行了分析,最后还介绍了在本次设计中有很多应用的访问数据库技术——ADO。 第四章是对网络办公自动化系统的具体设计,描述了整个系统详细的功能划分,描述了登录模块、公文处理模块、人力资源管理模块、设置模块的具体设计,并对设计源代码进行了注释分析。 本次设计充分利用ASP的VBScript语言的操作特性以及对数据库访问的ADO技术,提高了程序设计质量。 关键词:OA B/S结构web ASP Access

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