Error model of geomagnetic-field measurement and extended Kalman-filter based compensation method.

The real-time accurate measurement of the geomagnetic-field is the foundation to achieving high-precision geomagnetic navigation. The existing geomagnetic-field measurement models are essentially simplified models that cannot accurately describe the sources of measurement error. This paper, on the basis of systematically analyzing the source of geomagnetic-field measurement error, built a complete measurement model, into which the previously unconsidered geomagnetic daily variation field was introduced. This paper proposed an extended Kalman-filter based compensation method, which allows a large amount of measurement data to be used in estimating parameters to obtain the optimal solution in the sense of statistics. The experiment results showed that the compensated strength of the geomagnetic field remained close to the real value and the measurement error was basically controlled within 5nT. In addition, this compensation method has strong applicability due to its easy data collection and ability to remove the dependence on a high-precision measurement instrument

Improving the quality of soluble dietary fiber from Poria cocos peel residue following steam explosion

Poria cocos peel residue (PCPR) still contains much soluble dietary fiber (SDF), steam explosion (SE) treatment was applied to PCPR to create a superior SDF. Steam pressure of 1.2 MPa, residence period of 120 s, and moisture content of 13% were the optimized parameters for SE treatment of PCPR. Under optimized circumstances, SE treatment of PCPR enhanced its SDF yield from 5.24% to 23.86%. Compared to the original SDF, the SE-treated SDF displayed improved enzyme inhibition, including the inhibition of α-amylase and pancreatic lipase, also enhanced water holding, oil holding, water swelling, nutrient adsorption including cholesterol, nitrite ions, and glucose and antioxidant abilities. Additionally, it had a decreased molecular weight, improved thermal stability, and a rough surface with many pores of different sizes. Given that SDF had been improved physiochemical and functional characteristics thanks to SE treatment, it might be the excellent functional ingredient for the food business