Underwater four-quadrant dual-beam circumferential scanning laser fuze using nonlinear adaptive backscatter filter based on pauseable SAF-LMS algorithm

The phenomenon of a target echo peak overlapping with the backscattered echo peak significantly undermines the detection range and precision of underwater laser fuzes.To overcome this issue,we propose a four-quadrant dual-beam circumferential scanning laser fuze to distinguish various interference signals and provide more real-time data for the backscatter filtering algorithm.This enhances the algorithm loading capability of the fuze.In order to address the problem of insufficient filtering capacity in existing linear backscatter filtering algorithms,we develop a nonlinear backscattering adaptive filter based on the spline adaptive filter least mean square(SAF-LMS)algorithm.We also designed an algorithm pause module to retain the original trend of the target echo peak,improving the time discrimination accuracy and anti-interference capability of the fuze.Finally,experiments are conducted with varying signal-to-noise ratios of the original underwater target echo signals.The experimental results show that the average signal-to-noise ratio before and after filtering can be improved by more than31 d B,with an increase of up to 76%in extreme detection distance.

Effects of Biogas Slurry Recirculation on Anaerobic Digestion Performance of Maize Straw Silage

In order to investigate the effects of slurry recirculation technology on anaerobic digestion performance of maize straw silage,maize straw silage was fermented with recirculated biogas slurry,and the gas production,p H value,methane content,volatile organic acids( VFAs)contents,chemical oxygen demand( COD) removal rate and other indicators were studied. The results showed that the fermentation time was positively correlated with daily gas production,methane content,cumulative gas production,VFAs and COD removal rate. Although the p H value fluctuated,it was still in the normal reaction range. The daily gas production was about 1. 26 L. The acetic acid content increased first,then decreased,then increased,and finally stabilized. The biogas slurry recirculation technology saves water resources by 40 m L/d without affecting the normal gas production of anaerobic fermentation,and reduces the consumption of environmental resources. It has important development significance for the sustainable use of biomass resources.

Research Progress on Artificial Cultivation of Trhicoloma Matsutake and Theory of the Shiro in Changbai Mountains

Study on artificial cultivation of Tricholoma matsutake carried through by the present research group in Changbai Mountains in recent years was briefly reviewed in the paper, and then, the signifycance of cultivation. Mechanism of formation, hiberarchy, grouwth cycle and suitable living environment, were summarized.

A Wall-Crossing Formula and the Invariance of GLSM Correlation Functions

In this paper,we prove a wall-crossing formula,a crucial ingredient needed to prove that the correlation function of gauged linear-model is independent of the choice of perturbations.