The local signal-to-noise orthogonalization algorithm has been widely used in the community of seismic processing and imaging. It helps orthogonalize the signal-and-noise components in an elegant way so that the noise does not contain the signal leakage in seismic denoising. The traditional local signal-to-noise orthogonalization is based on solving a highly underdetermined, ill-posed inverse problem with local smoothness constraint. Due to the inversion nature, the local orthogonalization method requires a large number of iterations and thus is computationally demanding in large-scale applications. Here, we proposed a much accelerated signal-and-noise orthogonalization method, where we design an efficient way for calculating the orthogonalization weight. When new samples are involved in the calculation, we calculate the orthogonalization weight of the new samples by connecting them with the calculated weights of the previous samples. The orthogonalization weight needs to be smoothed and scaled after all samples have been processed to make the resulted orthogonalization weight smooth across the seismic data and match the amplitude level of the initially suppressed noise. In this way, we avoid iterations when calculating the orthogonalization weight. We apply the proposed method to several synthetic and field data examples, have a benchmark comparison with state-of-the-art algorithms, and demonstrate its much accelerated efficiency compared with the traditional local signal-and-noise orthogonalization.

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The Fe-catalyzed Fischer-Tropsch (FT) synthesis reaction is the core of the coal-to-liquids (CTL) process, which is an efficient route to convert coal into liquid fuels via synthesis gas (a mixture of CO and H₂). Conventional Fe-based FT catalysts convert typically 30% of the feed CO to undesirable CO₂during the FT step. A decrease of CO₂production in FT units can reduce the profitability of the overall CTL process. In this context, we synthesized phase-pure ϵ-Fe-carbide FT catalysts by careful control of the pretreatment and carburization conditions starting from Raney Fe. The resulting phase-pure Fe-carbide exhibits a low CO₂selectivity during the Fischer-Tropsch reaction. The developed preparation method can be applied to supported Fe catalysts and does not require expensive starting chemicals. The purity and durability of as-synthesized phase-pure ϵ-Fe-carbide catalyst under FT conditions were characterized in detail by in situ characterization techniques. A bulk phase-pure ϵ-Fe-carbide catalyst operated at 23 bar, 235 °C and a H₂/CO ratio of 1.5 shows stable performance with no deactivation during a 150 h pilot test. The catalyst is free of primary CO₂formation and presents reduced secondary CO₂formation compared to conventional Fe-based FT catalysts. These findings contribute to the development of new Fe-based FT catalysts for CTL processes.

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We propose an optimized uniform illumination design method for the ultraviolet (UV) light-emitting diode (LED) array module considering its application in UV light purification systems. First, the geometrical optics theory is used to evaluate the illumination of the purification layer receiving surface based on the luminescence intensity distribution in case of a single LED. Then, by combining the requirements of the spacing between the array module and purification layer, the ratio of the minimum and maximum illuminances of the purification layer, and illumination angle of a single LED, the optimal array spacing and simulation results of illuminance distributions are obtained by the dichotomy method along with the TracePro simulation. Finally, an uniform illumination measurement test has been designed for the array module to verify the accuracy of the simulation results. The research results demonstrate that the proposed method can realize an optimal design of the LED array module under different requirements with respect to the illumination uniformity, structure, and light source; furthermore, the proposed method exhibits important guiding significance for the design and development of UV light purification systems.@en