194 resultados para Micro-quartz
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973 Project of China [2006CB701305]; "863" Project of China [2009AA12Z148]; National Natural Science Foundation of China [40971224]
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A templateless, surfactantless, electrochemical approach is proposed to directly fabricate hierarchical flowerlike gold microstructures (HFGMs) on an indium tin oxide (ITO) substrate. The as-prepared HFGMs have been characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and cyclic voltammetry.
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A templateless, surfactantless, electrochemical route is proposed to directly fabricate hierarchical spherical cupreous microstructures (HSCMs) on an indium tin oxide (ITO) substrate. The as-prepared HSCMs have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD).
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Novel three-dimensional (3D) flowerlike MnWO4 micro/nanocomposite structure has been successfully synthesized for the first time. The synthesized products were systematically studied by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) and photoluminescence (PL) spectra. It is found that both reaction time and temperature have significant effects on the morphology of the products.
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In order to study the properties of Mg-Al-RE (AE) series alloys, the Mg-4Al-4RE-0.4Mn (RE= La, Ce/La mischmetal or Ce) alloys were developed. Their microstructures, tensile properties and corrosion behavior have been investigated. The results show that the phase compositions of Mg-4Al-4La-0.4Mn alloy consist of alpha-Mg and Al11La3 phases. While two binary Al-RE (RE = Ce/La) phases, Al11RE3 and Al2RE, are formed in Mg-4Al-4Ce/La-0.4Mn alloy, and Al11Ce3 and Al2Ce are formed in Mg-4Al-4Ce-0.4Mn alloy.
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Uniform Fe3O4 octahedral microcrystals with perfect appearance have been successfully synthesized by a Triton X100-assisted polyol process. During the polyols process for the preparation of Fe3O4 octahedra. the introduction of Triton X100 decreases significantly the needed concentration of NaOH. The results show that Fe3O4 octahedra are composed of eight triangular sheets, which are equilateral triangles. The edge size of Fe3O4 octahedron is about 4 mu m. The magnetic properties of Fe3O4 octahedral particles were evaluated on a SQUID magnetometer at room temperature.
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The in situ electrochemical quartz crystal microbalance(EQCM) technique was used to investigate the ion transport of immobilized heteropolyanions at a self-assembled monolayer(SAM) modified gold electrode during electrochemical redox process. A mixed transfer method was presented to analyse the abnormal change of resonant frequency based on the simultaneous insertion/extraction of different ions. The results indicate that the migration of HSO4- anions was indispensable in the redox process of the heteropolyan ions in a I mol/L H2SO4 solution and played a key role in the abnormal change of the resonant frequency. Such a change was attributed to different packing densities derived by means of differently immobilized methods.
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In this paper, we presented a novel covalent bonding process between two quartz wafers at 300 degrees C. High-quality wafer bonding was formed by the hydroxylization, aminosilylation and atom transfer radical polymerization (ATRP) of glycidyl methacrylate (GMA), respectively, on quartz wafer surfaces, followed by close contact of the GMA functional wafer and the aminosilylation wafer, the epoxy group opening ring reaction was catalyzed by the amino and solidified to form the covalent bonding of the quartz wafers. The shear force between two wafers in all bonding samples was higher than 1.5 MPa. Microfluidic chips bonded by the above procedures had high transparency and the present procedure avoided the adhesive to block or flow into the channel.
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Micro-banded textures developed from thin films of a main-chain thermotropic liquid crystalline chloro-poly(aryl ether ketone) in the melt were investigated using transmission electron microscopy (TEM). selective area electron diffraction, and atomic force microscopy techniques. The micro-banded textures were formed in the copolymer thin films after annealing at temperatures between 320 and 330degreesC, where a highly ordered smectic crystalline phase is formed without mechanical shearing. The micro-banded textures displayed a sinusoidal-like periodicity with a spacing of 150 nm and an amplitude of 2 rim. The long axis of the banded texture was parallel to the b-axis of an orthorhombic unit cell. In the convex regions, the molecular chains exhibited a homeotropic alignment, i.e. the chain direction was parallel to the film normal. In the concave re-ions, the molecular chains possessed a tilted alignment. In addition to the effects of annealing temperatures and times, the thickness of the film played a vital role in the formation of the banded texture. A possible formation mechanism of this banded texture vas also suggested and discussed. It was suggested that the micro-bands were formed during cooling.
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Self-doped polyaniline (PANI) micro-rings have been successfully generated electrochemically. The polymer forming rings were about 100 nm wide, and the ring diameter is tunable from several to dozens of micrometres depending on deferent current densities. The morphology of such nanostructured polyaniline rings was investigated and further confirmed with field-emission scanning electron microscopy (FE-SEM). Furthermore, the film was characterized using UV/visible spectroscopy and cyclic voltammetry. The bubble template formation mechanism of the micro-rings was also proposed. Such nanostructured materials synthesized electrochemically open up a new approach to surface morphology control.
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Micro-failure modes and statistical fragment lengths in the hybrid fiber and non-hybrid reference composites in the uniaxial tension were investigated. Similiar to the reference experiments, fibers in hybrid strong interface/medium interface fiber composites display a decrease in aspect ratio and an increase in interfacial shear stress (IFSS) with the increase of inter-fiber spacing. While for the fibers with weak interfaces in the hybrid strong interface/weak interface fiber composites, the aspect ratio increases and IFSS decreases with enlargement of inter-fiber spacing, which is contrary to other systems. Finite element numerical analysis was used to interpret the special phenomena.
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Ce3+ and/or Tb3+-doped LaPO4 nanocrystalline thin films and their patterning were fabricated by a sol-gel process combined with soft lithography on silicon and quartz glass substrates. The results of XRD indicated that the films began to crystallize at 700 degreesC. The 1000 degreesC annealed single layer films are transparent by eyes, uniform and crack-free with a thickness of about 200 nm and an average grain size of 100 nm. Patterned thin film with different band widths (5-50 mum) were obtained by micro-molding in capillaries technique. The luminescence and energy transfer properties of Ce3+ and Tb3+ were studied in LaPO4 films.
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In this paper, a calix[4]arene derivative, 5,11,17,23-butyl-25,26,27,28-tetra-(ethanoxycarbonyl)-methoxy-calix[4]arene (L), is investigated as a host to recognize alkali metal ions (Li+, Na+, K+, Rb+ and Cs+) at the interface between two immiscible electrolyte solutions (ITIES). Well-defined cyclic voltammograms are obtained at the micro- and nano-water \ 1,2-dichloroethane (W \ DCE) interfaces supported at micro- and nano-pipets.
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In this paper, the charge transfer across the micro-liquid/liquid interface supported at the orifice of a double-barrel micropipette, namely, a theta-pipette, is reported. Simple ion transfer(TMA(+)), facilitated ion transfer (potassium ion transfer facilitated by DB18C6), and electron transfer (ferrocene and ferri/ferrocyanide system) have been investigated by cyclic voltammetry. The experimental results show that a very thin aqueous film, linking both barrels filled with the aqueous solution and the organic solution respectively, can spontaneously be formed on the outer glass surface of such a double-barrel micropipette to construct a micro-liquid/liquid interface, which provides the asymmetry of diffusion field. Such device is demonstrated experimentally which can be employed as one of the simplest electrochemical cells to investigate the charge transfer across the liquid/liquid interface.