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991.
992.
Wuxia Li Georgi Lalev Stefan Dimov Hao Zhao D.T. Pham 《Applied Surface Science》2007,253(7):3608-3614
A dual-beam scanning electron microscopy (SEM)/focused-ion-beam (FIB) system was used to pattern fused silica substrates coated with a 15 nm thin Cr layer. The dimensions of fabricated features together with their surface morphology and profiles were investigated by SEM and atomic force microscopy (AFM). The study demonstrated that with the increase of the ion beam fluence the sputtering rate of the fused silica decreased non-linearly. Also, it was found that initially the sputtering rate increased with the increase of the beam current, after reaching a maximum value, it started decreasing when further beam current increment was performed. Compared with unprocessed areas, the surface finish of the features fabricated by FIB exhibited a significant improvement, and the ion fluence influence on the surface roughness of trenches with low aspect ratios could be considered as negligible. Using a fine beam probe, nano-gratings in the form of grooves with a width down to 54 nm and an aspect ratio higher than three were fabricated. The study showed that FIB machining could be an alternative technology to e-beam lithography for producing fused silica templates for UV nanoimprinting. 相似文献
993.
Pb0.97La0.02(Zr0.85Sn0.13Ti0.02)O3 (PLZST 2/85/13/2) antiferroelectric thin films were deposited on Pt(111)/Ti/SiO2/Si and LaNiO3(LNO)/SiO2/Si substrates through a modified sol-gel process. The phase structure and microstructure of PLZST 2/85/13/2 antiferroelectric thin films were analysed by x-ray diffraction (XRD), scanning electron microcopy (SEM) and field-emission SEM (FE-SEM). The antiferroelectric nature of the PLZST 2/85/13/2 thin films on two electrodes was demonstrated by the C-V (capacitance-voltage) and P-E (polarization-electric field) measurement. The maximum polarizations for PLZST 2/85/13/2 films on Pt and LNO electrodes were 42 and 18 μC/cm2, respectively. The temperature dependence of the dielectric property of the PLZST 2/85/13/2 films was measured under different dc electric fields. Also, the phase transformation of the PLZST 2/85/13/2 films was studied in detail as a function of temperature and dc electric field. 相似文献
994.
Hao Qian Ying Xue Zhang Sheng Mei Huang Zhi Yong Lin 《Applied Surface Science》2007,253(10):4659-4667
Functionalization of polystyrene films by the preferential surface enrichment of surface-modifying macromolecules (SMM) to achieve a hydrophilic surface with long effective duration is described. The comb-like amphiphilic copolymers (PKG-g-PS) based on styrene-maleic anhydride copolynier (SMA) backbone was synthesized by esterification of SMA with poly(ethylene glycol) (PEG). When PEG-g-PS was melt blended with polystyrene, the preferential surface enrichment of PEG-g-PS was much evident resulting in the large increase of the surface polarity. The effective duration of the surface functionalizatoin was also hugely extended as SMMs were added into the blends. Furthermore, more polyether chain segments on PEG-g-PS could selectively migrate to the surface by the inducement of polar solvent. Compared with the PEG-g-PS/PS and PEG/PEG-g-PS/PS blends, the surface polarity and the effective duration of surface modification both increased greatly when PEG-g-PS was used as the compatibilizer of PEG/PS blends. It was an effective solution to balance the conflict between the duration and efficiency of the surface-modifying additives. 相似文献
995.
Electrical resistivity and Seebeck coefficients of Y BaCo4−xZnxO7 (x=0.0,0.5,1.0,2.0) were investigated in the temperature range 350-1000 K. It was found that the electrical resistivity and activation energy increase with increasing Zn concentration, while Seebeck coefficients do not increase but decrease when electrical resistivity increases. We explained the increase of electrical resistivity and the drop of Seebeck coefficients for Zn-substituted samples by the decrease of carrier mobility, rather than of carrier concentration. The effect of oxygen absorption and desorption on the electrical resistivity and Seebeck coefficients was also investigated. An abrupt change of transport properties happens at about 650 K for x=0.0 and 0.5 samples measured in oxygen. For x=1.0 and 2.0 samples, however, such change disappears and the transport behavior in oxygen is almost same as that in nitrogen due to the significant suppression of oxygen diffusion caused by the higher Zn concentration in these samples. 相似文献
996.
High-Sensitivity Sensor Based on Surface Plasmon Resonance Enhanced Lateral Optical Beam Displacements 下载免费PDF全文
We present a new optical sensor based on surface plasmon resonance (SPIt) enhanced lateral optical beam displacements. Compared with the traditional SPIt methods, the new method provides higher sensitivity to the sensor system. Theoretical simulations show that the refractive index (RI) detection sensitivity of the SPR sensor based on the displacement measurement has a strong dependence on the thickness of the metal film. When the optimal thickness of the metal film is selected, the RI resolutlon of the SPIt sensor is predicted to be 2.2 × 10^-7 refractive index units (RIU). Furthermore, it is found that the incidence angle can be used as a parameter to adjust the operating range of the sensor to different refractive index ranges. 相似文献
997.
998.
研究了使用电化学沉积法于碱性条件下在柔性ITO衬底上制备Cu/Cu2O薄膜的方法。循环伏安曲线表明Cu2O与Cu的阴极峰分别位于-500 mV(vs Ag/AgCl)和-800 mV(vs Ag/AgCl)附近。利用循环伏安法考察了生长温度和电解液pH值等对Cu2O与Cu阴极峰电位的影响,阴极峰随生长温度的升高以及pH值的降低而略向阳极移动,沉积电流也随之相应增大。与弱酸性条件相比,上述两个阴极峰随pH值升高而移动的程度明显减小,这可能与碱性条件下C3H6O电离程度增大以及C3H6O根作为配体的过量程度有关。通过X射线衍射光谱和扫描电子显微镜的表征证实,在所研究的生长温度区间和pH值内可利用电化学沉积法在柔性ITO衬底上制备Cu/Cu2O纳米混晶薄膜。在相同的生长温度和pH条件下,电化学沉积电位对样品表面形貌和晶体性质具有较大影响。 相似文献
999.
用固相反应法制备系列Nd0.67Sr0.33MnOy(y=3.00-2.80)多晶样品.样品输运性质表现出自旋相关电致电阻特征.对氧含量等于化学计量样品,在测量温度范围内电阻不随负载电流变化,I-V曲线符合线性欧姆定律.对氧含量低于化学计量样品,当高于某一特征温度时,电阻变化符合线性欧姆定律;但低于这一特征温度时,电阻大小与负载电流有关,I-V曲线偏离线性规律;在绝缘体-导体相转变点附近,样品电阻随负载电流增大而迅速减小,表现出巨大电致电阻效应.对于y=2.85样品,当电流从1μA增加到30μA时,电致电阻接近80%.这种自旋相关的电致电阻行为与氧含量和界面有很大关系. 相似文献
1000.
Hongsheng Gao Hao Guo Xingliang Zheng Xiaoyu Huang 《Journal of polymer science. Part A, Polymer chemistry》2013,51(5):1099-1106
A series of well‐defined amphiphilic graft copolymer containing hydrophobic polyallene‐based backbone and hydrophilic poly(2‐(diethylamino)ethyl acrylate) (PDEAEA) side chains was synthesized by sequential living coordination polymerization of 6‐methyl‐1,2‐heptadiene‐4‐ol (MHDO) and single electron transfer‐living radical polymerization (SET‐LRP) of 2‐(diethylamino)ethyl acrylate (DEAEA). Ni‐catalyzed living coordination polymerization of MHDO was first performed in toluene to give a well‐defined double‐bond‐containing poly(6‐methyl‐1,2‐heptadiene‐4‐ol) (PMHDO) homopolymer with a low polydispersity (Mw/Mn = 1.10). Next, 2‐chloropropionyl chloride was used for the esterification of pendant hydroxyls in every repeating unit of the homopolymer so that the homopolymer was converted to PMHDO‐Cl macroinitiator. Finally, SET‐LRP of DEAEA was initiated by the macroinitiator in tetrahydrofuran/H2O using CuCl/tris(2‐(dimethylamino)ethyl)amine as catalytic system to afford well‐defined PMHDO‐g‐PDEAEA graft copolymers (Mw/Mn ≤ 1.22) through the grafting‐from strategy. The critical micelle concentration (cmc) was determined by ?uorescence spectroscopy with N‐phenyl‐1‐naphthylamine as probe and the micellar morphology was visualized by transmission electron microscopy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献