RESUMO
A dynamic sampling iterative phase retrieval method, which dynamically samples the Fourier intensity distribution of the reconstruction beam captured by the detector, is proposed to shorten the iterative number and decrease the phase error rate of phase retrieval in the phase-modulated holographic data storage. By the dynamic sampling method, that keeping relatively low frequency component of Fourier intensity spectrum at the beginning of iteration and gradually releasing more high frequency component at the subsequent iterations, we shortened the iterative number by 2 times and decreased the phase error rate to some extent because our method provided a better convergent path to the phase retrieval. We also believe the thought of our method can be used in more image retrieval fields.
RESUMO
Embedded data are used to retrieve phases quicker with high accuracy in phase-modulated holographic data storage (HDS). We propose a method to design an embedded data distribution using iterations to enhance the intensity of the high-frequency signal in the Fourier spectrum. The proposed method increases the antinoise performance and signal-to-noise ratio (SNR) of the Fourier spectrum distribution, realizing a more efficient phase retrieval. Experiments indicate that the bit error rate (BER) of this method can be reduced by a factor of one after 10 iterations.
RESUMO
Bayberry tannin immobilized on chitosan (CS-BT) was successfully prepared, and its adsorption performance was studied for aqueous solutions of rare earth ions. The as-prepared absorbents were characterized by Fourier transform infrared spectrometry and scanning electron microscopy. The equilibrium adsorption capacity was achieved in approximately 30 min. The adsorption process of CS-BT for Nd3+ was well fitted with a Freundlich model and the kinetics followed the pseudo-second-order rate equation. The maximum adsorption capacity for Nd3+ was 133.72 mg/g and dynamic adsorption characteristics of single ion (La3+, Ce3+, Nd3+) were investigated. The solution concentration was less than 30 mg/L when effluent volume was approximately 800 mL. Subsequently, the adsorbent column was desorbed by HNO3 solution. There was no significant loss of adsorption capacity after three cycles of regeneration, showing a satisfactory recyclability. Furthermore, CS-BT exhibited excellent dynamic adsorption performance of two mixed ions (La3+/Ce3+, La3+/Nd3+, Ce3+/Nd3+) and three mixed ions (La3+/Ce3+/Nd3+). The competitive adsorption capacity was La3+ < Ce3+ < Nd3+. The results indicate that the adsorption selectivity of column adsorption could provide a theoretical basis for the adsorption and separation of light rare earth ions. Therefore, this efficient adsorbent shows promising potential for the treatment of industrial wastewater.