861 resultados para One-step electrospin technique


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Details are given of a new software package MAXIMS which may be used to estimate the daily food consumption of fish. The software estimates the feeding times, the rates of ingestion and evacuation and related parameters. Two applications of the program are described. The first pertains to anchovy (Engraulis ringens ) with one feeding period per day, and the second one to juvenile cod (Gadus morhua ), which feed during dawn and dusk.

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We observed a transition from film to vertically well-aligned nanorods for ZnO grown on sapphire (0001) substrates by metalorganic chemical vapor deposition. A growth mechanism was proposed to explain such a transition. Vertically well-aligned homogeneous nanorods with average diameters of similar to 30, 45, 60, and 70 nm were grown with the c-axis orientation. Raman scattering showed that the E-2 (high) mode shifted to high frequency with the decrease of nanorod diameters, which revealed the dependence of nanorod diameters on the stress state. This dependence suggests a stress-driven diameter-controlled mechanism for ZnO nanorod arrays grown on sapphire (0001) substrates. (c) 2005 American Institute of Physics.

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Graphite, inexpensive and available in large quantities, unfortunately does not readily exfoliate to yield individual graphene sheets. Here a mild, one-step electrochemical approach for the preparation of ionic-liquid-functionalized graphite sheets with the assistance of an ionic liquid and water is presented. These ionic-liquid-treated graphite sheets can be exfoliated into functionalized graphene nanosheets that can not only be individuated and homogeneously distributed into polar aprotic solvents, but also need not be further deoxidized. Different types of ionic liquids and different ratios of the ionic liquid to water can influence the properties of the graphene nanosheets. Graphene nanosheet/polystyrene composites synthesized by a liquid-phase blend route exhibit a percolation threshold of 0.1 vol % for room temperature electrical conductivity, and, at only 4.19 vol %, this composite has a conductivity of 13.84 S m(-1), which is 3-15 times that of polystyrene composites filled with single-walled carbon nanotubes.

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Highly crystalline and nearly monodisperse In2O3 nanocrystals with both cube and flower shapes were successfully synthesized in one step through a facile aqueous solvothermal method for the first time, free of any surfactant or template. X-ray diffraction (XRD), transmission electron microscopy (TEM), selective area electron diffraction (SAED), and high-resolution transmission electron microscopy (HRTEM) were used to characterize the samples. In our work, the use of diethylene glycol (DEG) is a crucial factor for the formation of the In2O3 phase.

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In this paper, nanocrystalline YVO4:Eu3+ powders have been successfully synthesized via high-temperature solution-phase synthesis process. The nanocrystalline YVO4:Eu3+ particles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UVNis absorption spectra and luminescence spectra, luminescence decay curve and Fourier transform infrared (FT-IR), X-ray photoelectron spectra (XPS) respectively. The as-prepared nanocrystalline YVO4:Eu3+ particles are well crystallized with ellipsoidal morphology.

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A novel method for immobilization of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)Cl-2) on electrode surfaces based on the vapor-surface sol-gel deposition strategy is first demonstrated in this paper. Ru(bpy)(3)Cl-2 immobilized sol-gel (Ru(bpy)(3)Cl-2/sol-gel) films were characterized by UV-vis spectroscopy and field-emitted scanning electron microscopy (FE-SEM). These results showed that Ru(bpy)(3)Cl-2 was successfully incorporated into the silica sol-gel film. it was found that many irregular Ru(bpy)(3)Cl-2/sol-gel clusters were formed on surfaces through one deposition and thick sol-gel films were observed after further deposition.

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Nanoporous In2O3 nanocrystal clusters with high surface areas have been synthesized by a one-step solvent-thermal method at a relatively low temperature. On the basis of our experimental data and nanomaterial growth mechanism, a template-assistant dehydration accompanied by aggregation mechanism was proposed to explain their formation. Besides, the influence of the high-temperature treatment on their porous structure and optical properties were studied and compared by various technologies.

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A one-step method was developed to fabricate conductive graphene/SnO2 (GS) nanocomposites in acidic solution. Graphite oxides were reduced by SnCl2 to graphene sheets in the presence of HCl and urea. The reducing process was accompanied by generation of SnO2 nanoparticles. The structure and composition of GS nanocomposites were confirmed by means of transmission electron microscopy, x-ray photoelectron and Raman spectroscopy. Moreover, the ultracapacitor characteristics of GS nanocomposites were studied by cyclic voltammograms (CVs) and electrical impedance spectroscopy (EIS). The CVs of GS nanocomposites are nearly rectangular in shape and the specific capacitance degrades slightly as the voltage scan rate is increased. The EIS of GS nanocomposites presents a phase angle close to p/2 at low frequency, indicating a good capacitive behavior.

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We report here a facile method to obtain folic acid (FA)-protected gold nanoparticles (Au NPs) by heating an aqueous solution of HAuCl4/FA in which FA acts as both the reducing and stabilizing agent. The successful formation of FA-protected Au NPs is demonstrated by UV/Vis spectroscopy, transmission electron microscopy (TEM), selected-area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). ne intracellular uptake of these nanoparticles is facilitated by HeLa cells overexpressing the folate reporter, which itself is significantly inhibited by free FA in a competitive assay as quantified by inductively coupled plasma mass spectroscopy (ICP-MS). This simple one-step approach affords a new perspective for creating functional nanomaterials, and the resulting biocompatible, functional Au NPs may find some prospective applications in various biomedical fields.

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One-step synthesis of Ru (bpy)(3) Cl-2-immobilized (bpy = 2,2'-bipyridine) silica nanoparticles (Ru-silica nanoparticles) for use in electrogenerated-chemiluminescence (ECL) detection is reported. Ru-silica nanoparticles are prepared by using the Stober method. Compared with free Ru(bpy)(3)Cl-2, Ru-silica nanoparticles are seen to exhibit a red-shift of the UV-vis absorbance peak and a longer fluorescence lifetime, which are attributed to the electrostatic interaction of Ru(bpy)(3)(2+) and silica. Because silica nanoparticles are used as immobilization matrices, the surfaces of Ru-silica nanoparticles are easily modified or functionalized via the assembly of other nanoparticles, such as Au. For ECL detection, Au-colloid-modified Ru-silica nanoparticles are immobilized on a 3-mercaptopropyl-trimethoxysilane-modified indium tin oxide electrode surface by Au-S interaction; the surface concentration of electroactive Ru(bpy)(3)Cl-2 is obviously higher than that in silica films.

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Well-dispersed palladium nanoparticles in mesoporous SBA- 15 SiO2 were prepared in a facile one-step approach during sol-gel route under reductive atmosphere. X-ray diffraction (XRD) results indicate that as-synthesized nanocomposites basically remain ordered two-dimensional hexagonal mesostructure while transmission electron microscopy (TEM) study exhibits a well dispersion of palladium nanoparticles within the mesoporous SBA-15 channels. The size of Pd nanoparticles is approximately in the range of 5-10nm. However, the resulting nanocomposites exhibit a highly catalytic activity and reused ability at least after five recycles without ligand in air for both the Suzuki and Heck coupling reactions.

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A one-step method has been developed for synthesizing gold-polyaniline (Au@PANI) core-shell particles by using chlorauric acid (HAuCl4) to oxidize aniline in the presence of acetic acid and Tween 40 at room temperature. SEM images indicated that the resulting core-shell particles were composed of submicrometre-scale Au particles and PANI shells with an average thickness of 25 nm. Furthermore, a possible mechanism concerning the growth of Au@PANI particles was also proposed based on the results of control experiments.