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1.
INTRODUCTIONSinceSagiv(1980)investigatedthereactionofoctadecyltrichlorosilane(OTS)moleculeswithslideglassplatestoformselfassembledmonolayersin1980forthefirsttime,manyresearcheshavebeenconductedtostudytheformationofOTSmonolayersonmica,silicon,silicaandglasss… 相似文献
2.
报导了一种用于自组装膜研究的原子级平整金基底的制备方法。采用这种方法,得到金以(111)取 向的原子级平整基底,同时使用扫描探针显微镜(SPM)考察了该种金基底的自组装性能。 相似文献
3.
Aluminum nitride (AlN) thin films with high c-axis orientation have been prepared on a glass substrate with an Al bottom electrode by radio frequency (RF) reactive magnetron sputtering. Based on the analysis of Berg's hysteresis model, the improved sputtering system is realized without a hysteresis effect. A new control method for rapidly depositing highly c-axis oriented AlN thin films is proposed. The N2 concentration could be controlled by observing the changes in cathode voltage, to realize the optimum processing condition where the target could be fixed stably in the transition region, and both stoichiometric film composition and a high deposition rate could be obtained. Under a 500 W RF power of a target with a 6 cm diameter, a substrate temperature of 450 ℃, a target-substrate distance of 60 mm and a N2 concentration of 25%, AlN thin film with preferential (002) orientation was deposited at 2.3 μm/h which is a much higher rate than previously achieved. Through X-ray diffraction (XRD) analysis, the full width at half maximum (FWHM) of AlN (002) was shown to be about 0.28°, which shows the good crystallinity and crystal orientation of AlN thin film. With other parameters held constant, any increase or decrease in N2 concentration results in an increase in the FWHM of AlN. 相似文献
4.
MBE growth of ZnSxSe1−x thin films on ITO coated glass substrates were carried out using ZnS and Se sources with the substrate temperature ranging
from 270°C to 330°C. The XRD σ/2σ spectra resulted from these films indicated that the as-grown polycrystalline ZnSxSe1−x thin films had a preferred orientation along the (111) planes. The evaluated crystal sizes as deduced from the FWHM of the
XRD layer peaks showed strong growth temperature dependence, with the optimized temperature being about 290 °C. Both AFM and
TEM measurements of these thin films also indicated a similar growth temperature dependence. High quality ZnSxSe1−x thin film grown at the optimized temperature had the smoothest surface with lowest RMS value of 1.2 nm and TEM cross-sectional
micrograph showing a well defined columnar structure.
Project supported by the National Science Council of PRC (No. 59910161981) and RGC grant from the Hong Kong Government under
Grant (No. NS-FC/HKUST 35) 相似文献
5.
Xu Li-heng Chen Zhi-chun Li Yang-mei Lu De-shui Lin Xian-fu Yuan Jun 《浙江大学学报(A卷英文版)》2002,3(5):567-569
Pepsin was assembled on the surface of prepared poly (ethylene terephthalate) (PET-NH3
+) substrates. The composition and structure of the pepsin/PET-NH3
+ assembling films in different condition were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy
(AFM). 相似文献
6.
Surface morphologies of Zr52.5 Al10 Ni10 Cu15 Be12.5 bulk metallic glass after being rolled at both a temperature around T9 and near ( Tx - 50) K were investigated with a scanning electron microscopy. Macroscopic and microscopic observation results show that squamae, cracks, steps and wedges exist on the surface when the samples were rolled at temperatures around Ty. However, a smooth and fiat surface appears when the samples were rolled at temperatures near ( Tx - 50) K. These results indicate that the mode of deformation in the supercooled liquid region is a partially homogeneous flow at a temperature around T9, and a fully homogeneous one at temperatures near ( Tx - 50) K. According to the results, it is more feasible to roll the amorphous alloys at temperatures near ( Tx - 50) K to obtain parts with smooth and fiat surface. 相似文献
7.
Vashist SK Kaur I Bajpai RP Bharadwaj LM Tewari R Raiteri R 《Journal of Zhejiang University. Science. B》2006,7(9):683-685
We report an important observation that the surface conductivity of antibody layer immobilized on polylysine-coated glass
substrate decreases upon the formation of complex with their specific antigens. This change in conductivity has been observed
for both monoclonal and polyclonal antibodies. The conductance of monoclonal mouse IgG immobilized on polylysine-coated glass
substrate changed from 1.02×10−8 Ω−1 to 1.41×10−11 Ω−1 at 10 V when complex is formed due to the specific biomolecular interactions with rabbit anti-mouse IgG F(ab′)2. Similar behavior was observed when the same set up was tested in two clinical assays: (1) anti-Leishmania antigen polyclonal
antibodies taken from Kala Azar positive patient serum interacting with Leishmania promastigote antigen, and (2) anti-p21
polyclonal antibodies interacting with p21 antigen. The proposed concept can represent a new immunodiagnostic technique and
may have wide ranging applications in biosensors and nanobiotechnology too. 相似文献
8.
INTRODUCTION Monocrystalline SBN (Strontium barium nio-bium, SrxBa1?xNb2O6, denoted SBNx?100, where 0.25≤x≤0.75) solid solution, is currently being inves-tigated as potential material for many micro-device applications, such as piezoelectric infrared detectors, piezoelectric, electro-optic modulators, and holo-graphic storage (Koch et al., 1998), because SBN has one of the largest known linear electro-optic coeffi-cients (r33=1300 pm/V for SBN75), two orders of magnitude larger th… 相似文献
9.
Amorphous InGaZnO (a-IGZO) films were deposited on the corning eagle XG (EXG) glass substrates using magnetron sputtering
method. The structure, surface morphology, electrical and optical properties of these films were investigated by X-ray diffraction
(XRD), scanning electron microscopy (SEM), semiconductor parameter analyzer and spectrophotometry, respectively. The influence
of oxygen flow on the electrical properties of IGZO thin films was studied, showing that increasing oxygen flow changes the
resistivity with six orders of magnitude. The contact resistance of ITO/IGZO is 7.35×10−2 Ω·cm2, which suggests that a good ohmic contact exists between In2O3: Sn (ITO) and IGZO film. 相似文献
10.
Well-cubic perovskite lanthanum aluminate (LaAlO3) film on (110) silicon substrate was fabricated by sol-gel method with corresponding inorganic salts. Lanthanum acetate and
aluminum acetate glacial acetic acid solutions were prepared via ligand exchange starting from lanthanum nitrate hexahydrate
and aluminum nitrate hexahydrate after being refluxed. (CH3CO)2O removed nitrates and the crystallized H2O completely, acetylacetone (AcAc) was partially bidentated with metallic ion of the metallic acetates and formed La(OAc)3−x
(AcAc)
x
which were hydrolyzed into La(AcAc)3−x(OH)
x
by adding 10 ml 0.4% methyl cellulose (MCL) solution. The La(AcAc)3−x
(OH)
x
, polymerizing and combining with MCL, formed the LaAlO3 sol precursor with heteropolymeric structure and formed film easily. The epitaxial LaAlO3 film on Si(110) substrate was crystallized after being annealed in thermal annealing furnace for 650–750 °C/30 min. The morphologies
and microstructures were characterized. The refractive index of the LAO film was 1.942 to 2.007; the dielectric constant and
the dissipation factors were estimated to be 23–26 and 2.1×10−4−2.4×10−4 respectively.
Project (No. 2002CB613305) supported by the National Basic Research Program (973) of China 相似文献
11.
Refined empirical line method to calibrate IKONOS imagery 总被引:1,自引:0,他引:1
XU Jun-feng HUANG Jing-feng 《浙江大学学报(A卷英文版)》2006,7(4):641-646
INTRODUCTION To extract quantitative biophysical parameter such as leaf biomass and leaf chlorophyll concentra- tion from the remotely sensed imagery accurately, the effects of atmospheric scattering and absorption must be removed. Atmospheric effects add to or diminish true ground reflectance, if the atmospheric spectral features are not properly removed. A significant analytical bias could be introduced for data interpre- tation (Ben-Dor and Levin, 2000). Many approaches have been deve… 相似文献
12.
13.
Xi-qiang Li 《上海大学学报(英文版)》2000,4(2):163-166
Single crystal Ga
x
In1−x
As films have grown up on GaAs(100) substrate at 375°C and on InP(100) substrate at 390°C, respectively, by the method of
rf-sputtering with using undoped GalnAs polycrystal as target. However, on Si(100) or Si(111) substrates at 260–390°C, even
at 465°C, only polycrystalline films were obtained. In addition, the structure, composition, electrical characteristic and
optical properties of the Ga
x
In1−x
As films were investigated using X-ray diffraction (XRD), reflection of high energy electron diffraction (RHEED), energy dispersion
analyzer of X-ray (EDAX), Hall measurements and spectroscopic ellipsometry. 相似文献
14.
Elemental mercury has become a global concern because of its significant impact on human health and the ecosystem. A lot of effort has been put towards the removal of elemental mercury from the 2H-MoS2 (prismatic structure of MoS2). However, the mechanism of 1T-MoS2 (polytype structure of MoS2) in Hg0 capture remains unexplored. In this study, density functional theory (DFT) was adopted to investigate the adsorption mechanism of Hg on a 1T-MoS2 monolayer. The different possible adsorption positions on the 1T-MoS2 were examined. For different adsorption configurations, the changes in electronic property were also studied to understand the adsorption process. The results elucidated that chemisorption dominates the adsorption between Hg0 atoms and the 1T-MoS2. It was found that the TMo (on top of the Mo atom) position is the strongest adsorption configuration among all the possible adsorption positions. The adsorption of Hg0 atoms on the 1T-MoS2 monolayer is influenced by adjacent S and Mo atoms. The adsorbate Hg0 atom is found being oxidized on the TMo position of the 1T-MoS2 with an adsorption energy of ?1.091 eV. From the partial density of states (PDOS) analysis of the atoms, the strong interaction between Hg0 and the 1T-MoS2 surface is caused by the significant overlap among the d orbitals of the mercury atom and the s orbital of the S atom and p and d orbitals of the Mo atom. 相似文献
15.
王影影 《温州大学学报(社会科学版)》2009,(2):27-31
利用硅片上的金表面形成半胱胺自组装膜,并在半胱胺膜上接上荧光物质异硫氰酸荧光素,用落射荧光显微镜及电子倍增电荷耦合器件间接表征沉积在硅片上的各种金图形.该方法简便,灵敏度高,表征出的金图形清晰,最小直径为5—7μm. 相似文献
16.
A type of azobenzene-containing block copolymer polymethyl methacrylate-b-poly (n-butylmethacrylate-co-6-(4-(phenylazo) benzoate) hexyl methacrylate) (PMMA-b-(PnBMA-co-PAzoMA)) was synthesized by the atom transfer radical polymerization (ATRP). Macroinitiator polymethyl methacrylate (PMMA) was prepared by ATRP and used to initiate the copolymerization of monomer n-butyl methacrylate (nBMA) and azobenzene-based methacrylate monomer (AzoMA). Herein, three block copolymers with different molecular weights and block volume fractions were obtained and spin-coated on a silicon substrate or quartz plate before annealing at 180 °C for 14 h. The surface morphologies in these annealed copolymer films were observed by atomic force microscopy (AFM). Bicontinuous stripe or island patterns with different sizes were formed dependent on the film thickness. These ordered patterns are considered to be formed arising from the dewetting process of the surface layer in the copolymer film. Photoisomerization of azobenzene units in the copolymer films changed the dewetting behaviors of the surface layer of the thin film. Therefore, some copolymer annealed films showed a reversible morphology conversion between bicontinuous stripe and island structure when exposed to UV light and upon being stored in the dark. It was found that the composition of the block copolymer had obvious influences on the photoinduced morphology conversion behaviors in these copolymer thin films. When the volumes of PnBMA and PAzoMA phases in the block copolymer were large enough, the surface morphology could be modulated by UV light irradiation and storage in the dark. This work proposes a new possibility for photoinduced control and design of the dewetting processes of thin films using a linear block copolymer. 相似文献
17.
Heparin was grafted onto polycarbonate urethane (PCU) surface via a three-step procedure utilizing α, ωdiamino-poly(ethylene glycol) (APEG, M n =2 000) as a spacer. In the first step, isocyanate functional groups were introduced onto PCU surface by the treatment of hexamethylene diisocyanate (HDI) in the presence of di-n-butyltin dilaurate (DBTDL) as a catalyst. In the second step, APEG was linked to the PCU surface to obtain the APEG conjugated PCU surface (PCU-APEG). In the third step, heparin was covalently coupled with PCU-APEG in the presence of N-hydroxysuccinimide (NHS) and 1-ethyl-3-(3-dimethylamidopropyl) carbodiimide (EDAC). The amount of heparin (1.639 μg/cm 2 ) covalently immobilized on the PCU-APEG surface was determined by the toluidine blue method. The modified surface was characterized by water contact angle, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The hemocompatibility was preliminarily studied by platelet adhesion test. The results indicated that heparin was successfully grafted onto the PCU surface, and meanwhile the hydrophilicity and hemocompatibility of the modified PCU surface were improved significantly compared with the blank PCU surface. 相似文献
18.
19.
ZAKHARENKO A. A. 《浙江大学学报(A卷英文版)》2007,8(7):1065-1076
In this paper, the obtained experimental results concerning creation of bulk elementary excitations (BEEs) in iso-topically pure liquid 4He at low temperatures ~60 mK are discussed. Positive rotons’ (R -rotons) creation by a pulsed heater was studied. Signals were recorded for the following quantum processes: quantum evaporation of 4He-atoms from the free liq- uid-helium surface by the BEEs of the liquid helium-II, and BEEs reflection from the free surface back into the bulk liquid. Typical signals are shown, and ratios of signal amplitudes are evaluated. For long heater pulses from 5 to 10 μs, appearance of the second atomic cloud consisting of evaporated 4He-atoms was observed in addition to the first atomic cloud. It is thought that the first atomic cloud of the evaporated helium atoms consists of very fast 4He-atoms with energies ~35 K evaporated by positive rotons with the special energies ~17 K (~2ER~2×8.6 K with ER representing the roton minimum energy) corresponding to the third non-dispersive Zakharenko wave. The second cloud of slower 4He-atoms was created by surface elementary excitations (SEEs or ripplons) possessing the special energies ~7.15 K representing the binding energy. It was assumed that such SEEs can be created by phonons incoming to the liquid surface with special energies ~6.2 K corresponding to the first non-dispersive Zakharenko wave, which can interact at the liquid surface with the same phonons already reflected from the surface for long heater pulses. Also, some pulsed-heater characteristics were studied in order to better understand the features of such heaters in low temperature experi- ments. 相似文献
20.
Pd77Cu6Si17 (PCS) tbin film metallic glasses (TFMGs) with high glass forming ability and hardness were selected as a hard coating for improving the surface hardness ofAZ31 magnesium alloy. Both microindentation and nanoindentation tests were conducted on specimens with various PCS film thicknesses from 30 to 2000 nm. The apparent hardness and the relative indenta- tion depth (fl) were integrated using a quantitative model. The interaction parameters involved and relative hardness values were extracted from iterative calculations. According to the results, surface hardness can be enhanced greatly by PCS TFMGs in the shallow region, followed by gradual decrease with increasing fl ratio. In addition, specimens with thinner coatings (e.g., 200 nm) showed greater substrate-film interaction and those with thick coatings (e.g., 2000 nm) became prone to film cracking. The op- timum TFMG coating thickness in this study was estimated to be around 200 nm. 相似文献