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101.
In this work, we presented a new method which directly acts on the surface of the Ti sheet by mechanical micro-etching using a grating ruling engine. The effect of the pre-pattern on the morphology and growth speed of TiO2 nanostructure formed on the Ti sheet with the traditional anodization method was investigated. A novel wall structure was observed and the growth speed of TiO2 nanotube (NT) was greatly affected by the pre-pattern. The wall structure increases the surface-to-volume ratio of the nanotube arrays. The new method provided the possibility of further optimization of fast growth of TiO2 nanostructure and improving the efficiency of dye-sensitized solar cell (DSSC) and photocatalysis. 相似文献
102.
Saeed?Rastegar Naser?MohammadiEmail author Reza?Bagheri 《Colloid and polymer science》2004,283(2):145-153
The morphology of a quaternary blend containing a diglycidyl ether of bisphenol-A (DGEBA), a thermoplastic modifier (PMMA), a phase-separating curing agent (diaminodiphenylmethane, DDM), and a non-phase-separating curing agent (methylenebis(3-chloro-2,6-diethylaniline, MCDEA) was studied as a function of volume fraction of the thermoplastic modifier and fractional concentration of the curing agents in their mixture. It was found that using mixtures of curing agents a co-continuous morphology could be obtained at PMMA concentrations as low as 2.5 volume percent. Using FTIR spectroscopy it was proved that specific interactions are present between PMMA and individual amine curing agents. On the other hand, there was no detectable specific interaction between PMMA and DGEBA. By analyzing the micro-indentation hardness data of the cryo-fractured samples and putting forward the intrinsic hardness concept, it was proposed that the co-continuous morphology is inherently more effective than the other morphologies in changing the mechanical properties of the above-mentioned multi-component blends. 相似文献
103.
Hyun Jong Park Olga Kryliouk Tim Anderson Dmitry Khokhlov Timur Burbaev 《Physica E: Low-dimensional Systems and Nanostructures》2007,37(1-2):142
InN films and nanorods were grown by hydride metalorganic vapor phase epitaxy (H-MOVPE) and the effects of growth temperature, and NH3/TMIn and HCl/TMIn ratios on morphological dependences were studied. The growth habit of InN varied from thin film to microrod to nanorod to no deposition as the growth conditions were changed about transition from growth to etching conditions. The growth and etch regimes were also predicted by chemical equilibrium calculations of In–C–H–Cl–N-inert system. The optical properties of InN nanorods and columnar structured films were measured by room temperature PL and a maximum intensity was observed at 1.08 eV for both structures. 相似文献
104.
Venkata Bharat Ram Boppana 《Journal of solid state chemistry》2011,184(5):1054-1062
We report the first instance of a hydrothermal synthesis of zinc germanate (Zn2GeO4) nano-materials having a variety of morphologies and photochemical properties in surfactant, template and catalyst-free conditions. A systematic variation of synthesis conditions and detailed characterization using X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, Raman spectroscopy, electron microscopy, X-ray photoelectron spectroscopy and small angle X-ray scattering led to a better understanding of the growth of these particles from solution. At 140 °C, the zinc germanate particle morphology changes with pH from flower-shaped at pH 6.0, to poly-disperse nano-rods at pH 10 when the Zn to Ge ratio in the synthesis solution is 2. When the Zn to Ge ratio is reduced to 1.25, mono-disperse nano-rods could be prepared at pH 7.5. Nanorod formation is also independent of the addition of cetyltrimethylammonium bromide (CTAB), in contrast to previous reports. Photocatalytic tests show that Zn2GeO4 nano-rods (by weight) and flower shaped (by surface area) are the most active for methylene blue dye degradation among the synthesized zinc germanate materials. 相似文献
105.
Wenwei Zhao Li Yu Xiaoguang Zhong Yuefang Zhang Jiazhen Sun 《Journal of Macromolecular Science: Physics》2013,52(3):231-237
Thermal behavior and morphology of blends prepared by solution casting of mixtures of chitosan and poly(ethylene oxide) were studied by means of differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The preliminary results indicate that both melting point and crystallinity depend on the composition of the blends, and that they exhibit minimum values when the blend contains 50% chitosan. From the prediction of melting point depression analysis, the compatibility of the blends shows a transition at this specific composition. This conclusion was further confirmed by observation of the morphology. 相似文献
106.
The fundamental optical storage mechanism of the laser light eddressable azobenzene moiety is briefly introduced.A modular and flexible synthesis design furnishes polyester matrices covalently integrating cyanoazobenzene in regularlyspaced side chains. Thin films of these materials are particularly well suited for holographic storape. Notable figures of meritsof liquid crystalline polyesters are response time to blue-green laser light of the order of nanoseconds, storage capacityexpressed as 5000 lines/mm, and high, permanent (almost nine years) diffraction efficiency of the order of 50% or greater,and erasability, The implications of the main chain nature for polyester morphology and for the permanency of the inducedanisotropy are discussed, The design and methods of preparation of other significantly different polymer scaffolds supportingcyanoazobenzene are elaborated. Oligopeptides always result in amorphous materials, whereas copolymethacrylates anddendritic or hyperbranched polyesters provide some materials that exhibit liquid crystallinity. However, none of these scaffolds affords materials that result in permanent anisotropy when exposed to interfering laser light. 相似文献
107.
B.-E. Schuster A. Haug M. Häffner M. M. Blideran M. Fleischer H. Peisert D. P. Kern T. Chassé 《Analytical and bioanalytical chemistry》2009,393(8):1899-1905
We present a spectroscopic and microscopic characterization of the chemical composition, structure, and morphology of two
commercial negative resists using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS),
and atomic force microscopy (AFM). For this purpose, films of a novolak-based resist (ma-N 2400) and hydrogen silsesquioxane
(HSQ) are treated under different conditions (temperature, deep ultraviolet (DUV) exposure, CHF3 plasma). Topographic AFM images show that both heating and DUV exposure strongly affect the surface morphology of as-prepared
ma-N 2400 resist films. These different treatment conditions also lead to decreasing roughnesses, which indicates structural
reorganization. Furthermore, the decrease of the photoactive compound (bisazide) in the ma-N 2400 resist films, observed in
FTIR spectra, suggests cross-linking of the resist after CHF3 plasma treatment, heating, or DUV exposure. XPS measurements on different CHF3 plasma-treated surfaces reveal that a structurally homogeneous fluorine-containing polymer is generated that is responsible
for an enhanced etch resistance. FTIR measurements of HSQ films show a correlation between the degree of HSQ cross-linking
and baking time. 相似文献
108.
This paper presents the results of morphological and ac electrical investigations on low density polyethylene (LDPE) composites with octavinyl polyhedral oligomeric silsesquioxane (POSS). It has been shown that at low loadings, the frequency dependence of dielectric constant and dielectric loss for the LDPE/POSS composites showed unusual behaviors when compared with conventional (micro-sized particulates) composites. The ac breakdown strength was measured and statistical analysis was applied to the results to determine the effects of POSS loadings on the dielectric strength of LDPE. The morphological characterization showed that the presence of POSS additives apparently altered the supermolecular structure of LDPE and resulted in more homogeneous morphology when compared with the neat LDPE. The structure-property relationship was discussed and it was concluded that the final dielectric properties of the composites were determined not only by the incorporation of POSS additives but also by the supermolecular structure of LDPE. Rheological analyses of LDPE/POSS composite were also performed and the results showed that the octavinyl-POSS had good compatibility with LDPE. 相似文献
109.
J.Y. Park J.H. Seo J.Y. Kim C.N. Whang S.S. Kim D.S. Choi K.H. Chae 《Applied Surface Science》2005,240(1-4):305-311
Alkali metals (AM) on semiconductors have been investigated as a simple model system for the metal-semiconductor interfaces due to their simple electronic structures. Especially, cesium (Cs) on Si(0 0 1) surface has been studied with various experimental techniques. In this study, we investigated the atomic structure of initial Cs adsorption on Si(0 0 1)-(2×1) surface using coaxial impact collision ion scattering spectroscopy. When Cs atoms are adsorbed on Si(0 0 1)-(2×1) up to 0.2 ML at room temperature, the initial adsorption site is on-top T3 site with poor periodicity and the length of Si dimer is reserved as in the clean Si(0 0 1) surface. It is also found that Cs atoms adsorbed on Si(0 0 1) surface with a height of 2.83±0.05 Å from the second layer of Si(0 0 1) surface. 相似文献
110.
Thermally reversible light scattering (TRLS) films are prepared from ultraviolet (UV) curing of polyether urethane diacrylate (PEUDA) with dispersed low molecular weight 1-octadecanol (OD). Depending on the temperature, the OD domains are crystalline or amorphous and this produce opaque or transparent films in a reversible way. Stable optically transparent and light scattering states are obtained after 100 successive heating–cooling cycles. Moreover, morphologies of the OD domains could be varied significantly with the cure temperature and this led to notable discrepancy in optical properties. By using an UV-mask and curing in two steps at different temperatures, complex patterns could be recorded in the film that were encoded at high temperatures (60 °C) and revealed at low temperatures (i.e., at room temperature), which makes the film a candidate for thermo-optical recording medium. 相似文献