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991.
992.
993.
激光三角法是表面形貌非接触测量中的一种常用方法,在几何测量领域应用广泛。传统的激光三角法采用高斯光束作为指示光源,在机械扫描机构的配合下,通过对被测表面逐点扫描完成表面形貌的测量。采用新型的无衍射光替代传统激光光源,解决了普通高斯光束存在的“焦深”问题,简化了机械结构。并采用基于灰色系统理论的灰色滤波进行表面形貌的分离与评定,克服了原有方法对测量数据样本量和统计特性的依赖,并通过实验表明该系统能够准确地完成表面形貌的三维测量,所提出的灰色评定方法能够比较有效地进行表面形貌的分离与评定。 相似文献
994.
995.
Hao Cheng Xiujian Zhao Xiaotao Sui Yuli Xiong Jiang Zhao 《Journal of nanoparticle research》2011,13(2):555-562
CdS quantum dot (Qd)-sensitized TiO2 nanotube array photoelectrode is synthesised via a two-step method on tin-doped In2O3-coated (ITO) glass substrate. TiO2 nanotube arrays are prepared in the ethylene glycol electrolyte solution by anodizing titanium films which are deposited
on ITO glass substrate by radio frequency sputtering. Then, the CdS Qds are deposited on the nanotubes by successive ionic
layer adsorption and reaction technique. The resulting nanotube arrays are characterized by scanning electron microscopy,
X-ray diffraction (XRD) and UV–visible absorption spectroscopy. The length of the obtained nanotubes reaches 1.60 μm and their
inner diameter and wall thickness are around 90 and 20 nm, respectively. The XRD results show that the as-prepared TiO2 nanotubes array is amorphous, which are converted to anatase TiO2 after annealed at 450 °C for 2 h. The CdS Qds deposited on the TiO2 nanotubes shift the absorption edge of TiO2 from 388 to 494 nm. The results show that the CdS-sensitized TiO2 nanotubes array film can be used as the photoelectrode for solar cells. 相似文献
996.
Xiangbo Meng Mihnea Ionescu Mohammad Norouzi Banis Yu Zhong Hao Liu Yong Zhang Shuhui Sun Ruying Li Xueliang Sun 《Journal of nanoparticle research》2011,13(3):1207-1218
This study attempted to synthesize one-dimensional (1D) coaxial nanotubes of Fe2O3 based on carbon nanotubes (CNT@Fe2O3) via atomic layer deposition (ALD) using ferrocene and oxygen as precursors. Results disclosed that undoped CNTs were suitable
for the ALD of Fe2O3 (ALD-Fe2O3) only if they were chemically functionalized, due to their inert surface nature. It was further demonstrated that the effects
of both covalent and non-covalent methodologies were limited in functionalizing undoped CNTs, leading to random and non-uniform
deposition of Fe2O3. In sharp contrast, it was found that, as an alternative, nitrogen-doped CNTs (N-CNTs) contributed uniform and tunable ALD-Fe2O3, due to their active surface nature induced by incorporated N atoms. Consequently, various 1D heterostructural coaxial nanotubes
were obtained with well-controlled growth of Fe2O3 on N-CNTs. For a better understanding, the underlying mechanisms were explored based on different N-doping configurations.
In addition, high-resolution transmission electron microscopy and X-ray diffraction jointly demonstrated that as-deposited
Fe2O3 is single-phase crystalline α-Fe2O3 (hematite). The as-synthesized heterostructural coaxial nanotubes of CNT@Fe2O3 may find great potential applications in photocatalysis, gas-sensing, and magnetic fields. 相似文献
997.
Hao Shen Seungpyo Hong Robert K. Prud’homme Ying Liu 《Journal of nanoparticle research》2011,13(9):4109-4120
We present an experimental study of self-assembled polymeric nanoparticles in the process of flash nanoprecipitation using
a multi-inlet vortex mixer (MIVM). β-Carotene and polyethyleneimine (PEI) are used as a model drug and a macromolecule, respectively, and encapsulated in diblock
copolymers. Flow patterns in the MIVM are microscopically visualized by mixing iron nitrate (Fe(NO3)3) and potassium thiocyanate (KSCN) to precipitate Fe(SCN)
x
(3−x)+. Effects of physical parameters, including Reynolds number, supersaturation rate, interaction force, and drug-loading rate,
on size distribution of the nanoparticle suspensions are investigated. It is critical for the nanoprecipitation process to
have a short mixing time, so that the solvent replacement starts homogeneously in the reactor. The properties of the nanoparticles
depend on the competitive kinetics of polymer aggregation and organic solute nucleation and growth. We report the existence
of a threshold Reynolds number over which nanoparticle sizes become independent of mixing. A similar value of the threshold
Reynolds number is confirmed by independent measurements of particle size, flow-pattern visualization, and our previous numerical
simulation along with experimental study of competitive reactions in the MIVM. 相似文献
998.
Based on the atomic superposition approximation (ATSUP) and first-principles pseudopotential plane-wave methods, the bulk and Mg mono-vacancy positron lifetime of magnesium oxide were calculated using Arponen-Pajamme and Borofiski-Nieminen positron-annihilation-rate interpolation formula respectively. The calculated values are in good agreement with experimental values and the first-principles method gives more convincing results. The positron annihilation density spectra analysis reveals that positrons mainly annihilate with valence electrons of oxygen atoms when the magnesium-vacancy appears within magnesium oxide. 相似文献
999.
The band gap of a photonic crystal (PhC) cavity intrinsically avoids HOM problems. In this paper, we present a new PBG structure based on the possible advantage of using hybrid structures and aperiodic lattices. This novel hybrid and aperiodically ordered cavity was designed for apparently higher Q-factor (more than 10300) and achieving large accelerating field gradient. The HOMs in the cavity are able to be absorbed efficiently. 相似文献
1000.
ZHANG Jun JIN YaXin WANG HanBin YE Cong TONG WeiMing & WANG Hao Faculty of Physics Electronic Technology Hubei University Wuhan China 《中国科学:物理学 力学 天文学(英文版)》2011,(7)
Highly textured Ni nanowire arrays were fabricated into anodic aluminum oxide(AAO) templates by pulse DC electrodeposition.The applied voltage and pH value of electrolytes were found strongly affecting the microstructure and magnetic properties of Ni nanowire arrays.Low applied potential and pH value both prefer to form polycrystalline fcc Ni nanowires.Increasing the applied potential or pH value favors the Ni [220] texture and even eventually forms the [220] oriented single crystal Ni wires,while exorbitan... 相似文献