3/31/2023 0 Comments Fft imagej![]() ![]() The structures of the calcined nanofibers were determined by Raman spectroscopy and X-ray diffraction (XRD), which clearly indicated the formations of SrTiO 3 and NiO nanofiber structures. The images showed fluctuation in the fiber diameters because of the two different polymeric solutions electrospun at the same time. The morphology and dimensions of the nanofibers were observed by scanning electron microscopy (SEM). Ultraviolet (UV) spectrophotometry, Fourier transform infrared radiation (FTIR), and differential scanning calorimeter (DSC) techniques were used to characterize the structural properties of the SrTiO 3-NiO nanocomposite fibers. Water contact angles were determined to identify surface hydrophobicity of the nanofiber films. The electrospun nanofiber samples were annealed at 600 C for two hours in air in order to remove the organic part and crystallize the amorphous SrTiO 3-NiO nanofibers. This coaxial electrospinning method generated uniform-size, defect-free fibers. Nickel oxide was mixed with the solution to form the outer (shell) layer. Polyacrylonitrile (PAN) polymer was dissolved in dimethylformamide (DMF) at a weight ratio of 10:90. First, poly (vinyl pyrrolidone) (PVP) was dissolved in deionized (DI) water, and then titanium (IV) isopropoxide and strontium nitrate were added into the solution to form the inner (core) layer. The coaxial electrospinning process was used to produce core/shell strontium titanate/nickel oxide (SrTiO 3-NiO) nanofibers. TMA determined the coefficient of thermal expansion (CTE), indicating an improvement in stability of the composite material, which can be useful for structural health monitoring (SHM) as well as lightning strikes and electromagnetic interference shielding applications of new carbon fiber composites. The vibration peak of the C À À À À À À N group also appeared at 1,452 cm À1 spectrum. The highest stretching peak of the CH 2 group was recognized within the range of 2,500-2,800 cm À1 for the carbonized fibers. A Raman spectroscopy peak around 897 cm À1 indicated formation of the g-phase of the carbonized PAN fibers. Dynamic mechanical analysis (DMA) tests exhibited a shift of the glass transition temperature of the carbonized PAN nanofiber/composite, which may be helpful for high-temperature applications of the present composites. ![]() Thermal mechanical analysis (TMA) measurements clearly showed that significant reinforcement was achieved for the pre-preg/ carbonized PAN fiber composites because of the enhanced interfacial bonding between the PAN nanofibers and the matrix. The resultant composite panels were cut into small pieces and subjected to a number of different characterization techniques. The PAN electrospun fibers were oxidized at 280 C in an ambient condition for 1 hr and then carbonized at 850 C for 1 hr in an argon (Ar) gas atmosphere. ![]() The FFT of the original image is obtained by the following code.Unidirecitonal pre-preg carbon fibers of ten peel plies were laid up at 0-, 45-, À45-, and 45-degree stacking sequences on a flat and smooth aluminum (Al) plate, and then carbonized electrospun polyacrylonitrile (PAN) nanofibers were placed on top of the last ply prior to vacuum curing in a vacuum oven. From the 2D FFT, I wish to calculate the amplitude of the FFT averaged over a circle vs the distance in pixels by varying the radius of the pixels which is effectively the distance in pixels. I am trying to obtain 2D FFT of an image. ![]()
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