Setia Budi, Sukro Muhab, Agung Purwanto, Budhy Kurniawan and Azwar Manaf
The effect of electrodeposition potential on the magnetic properties of the FeCoNi films has been reported in this paper. The FeCoNi electrodeposition was carried out from sulfate solution using potentiostatic technique. The obtained FeCoNi films were characterized by X-ray diffractometer (XRD), atomic absorption spectrometer (AAS) and vibrating sample magnetometer (VSM). It has been shown that the electrodeposition potential applied during the synthesis process determines the magnetic characteristics of FeCoNi films. The more negative potential is applied, the higher Ni content is in the FeCoNi alloy. At the same time, Co and Fe showed almost similar trend in which the content decreased with an increase in applied potential. The mean crystallite size of FeCoNi films was ranging from 11 nm to 15 nm. VSM evaluation indicated that the FeCoNi film is a ferromagnetic alloy with magnetic anisotropy. The high saturation magnetization of FeCoNi film was ranging from 86 A·m2/kg to 105 A·m2/kg. The film is a soft magnetic material which was revealed by a very low coercivity value in the range of 1.3 kA/m to 3.7 kA/m. Both the saturation magnetization and coercivity values decreased at a more negative electrodeposition potential.
This study developed a simple wire phantom and an algorithm to automatically measure the modulation transfer function (MTF) in computed tomography (CT) and implemented it to evaluate the effect of focal spot size and reconstruction filter type. The phantom consisted of a resin cylinder filled with water, with a tin wire of diameter 0.1 mm positioned along the center of the cylinder. The automated MTF algorithm used an axial image of the phantom and comprised several steps. The center position of a region of interest (ROI) was automatically determined at the center of the wire image. The pixels were then summed along the y-direction to obtain the profile of the pixel values at a point along the x-direction. Following this, both edges of the profile were made equal to zero. The profile curve was then normalized so that the total of all the data was equal to unity. The normalized profile curve is the line spread function (LSF), and the MTF curve was obtained by taking its Fourier transform. Our system (phantom and algorithm) is able to differentiate the MTFs of CT images from different focal sizes and reconstruction filter types.