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Swarm intelligence method is an effective way to improve the particle degradation and sample depletion of the traditional particle filter. This paper proposes a particle filer based on the gravitation field algorithm (GF-PF), and the gravitation field algorithm is introduced into the resampling process to improve particle degradation and sample depletion. The gravitation field algorithm simulates the solar nebular disk model, and introduces the virtual central attractive force and virtual rotation repulsion force between particles. The particles are moves rapidly to the high-likelihood region under action of the virtual central attractive force. The virtual rotation repulsion force makes the particles keep a certain distance from each other. These operations improve estimation performance, avoid overlapping of particles and maintain the diversity of particles. The proposed method is applied into INS/gravity gradient aided navigation, by combining the sea experimental data of an inertial navigation system. Compared with the particle swarm optimization particle filter(PSO-PF) and artificial physics optimized particle filter (APO-PF), the GF-PF has higher position estimate accuracy and faster convergence speed with the same experimental conditions.

Data of logging-while-drilling (LWD) log, formation pressure from MDT (modular formation dynamics tester) measurement, and production performance are used to study the relationship between depletion degree (formation pressure), initial production GOR (gas oil ratio) of single well and LWD response of depletion development in reservoirs. The results indicate that the overlap between density and neutron porosity curves from LWD data are related to reservoir depletion degree and production GOR when the formation pressure is less than the bubble point pressure. Larger overlap between the two curves corresponds to lower formation pressure and higher GOR. The relationship between the formation pressure, production GOR and porosity difference between density and neutron porosities can be derived from multi-analysis and regression. Through the analysis of the actual data from Block II of DLL Oilfield, empirical formulas have been established to predict formation pressure and production GOR from the porosity difference between density and neutron porosities. The predicted results correspond with MDT measurements and production GOR data, which proves the high reliability of the methods. Key words: Depletion degree, production GOR, LWD, density porosity, neutron porosity, carbonate reservoir

Soft pumps have the potential to transform industries including soft robotics, wearable devices, microfluidics and biomedical devices, but their efficiency and power supply limitations hinder prolonged operation. Here, we report a self-powered triboelectric-electrohydrodynamic pump, which combines a soft electrohydrodynamic pump driven by an electrostatic generator, specifically a triboelectric nanogenerator. The triboelectric nanogenerator collects ambient energy and converts it into high-voltage power source, allowing it to self-power an electrohydrodynamic pump and thus eliminating the need for external power supply. Using power management circuit, geometric shape optimization, and stacking methods, we achieve a maximum pressure of 4.49 kPa and a maximum flow rate of 502 mL/min. We demonstrate the pump's versatility in applications such as self-powered soft actuators, oil pumping in microfluidics, and oil purification. The triboelectric-electrohydrodynamic pump holds promising applications, and offers new insights for the development of fully self-powered systems. Soft pumps have applications across various fields but are constrained by their dependence on external power sources. Here, the authors present a battery-free electrohydrodynamic soft pump that utilizes a triboelectric nanogenerator to harvest ambient energy, serving as the driving source for dielectric fluid flow. [ABSTRACT FROM AUTHOR]

The novel coronavirus disease 2019 (COVID‐19) causes severe respiratory illness and is involved in ischemic stroke. Aimed to investigate the inflammatory markers and possible prognosis of COVID‐19‐related ischemic stroke in a special outbreak period after lifting of COVID‐19 control measures in China, we conducted a multicenter retrospective analysis in southern China at three centers in Shenzhen. We included patients diagnosed with acute ischemic stroke or transient ischemic attack after infection with COVID‐19 as the COVID‐19‐related ischemic stroke group and those only diagnosed with acute ischemic stroke or transient ischemic attack as the control group. In this study, the proportion of female patients, admission heart rate, and comorbid coronary heart disease and the proportion of cryptogenic stroke were higher, while the history of prior stroke was lower in the COVID‐19‐related ischemic stroke group. The COVID‐19‐related ischemic stroke group also exhibited elevated levels of monocytes, fibrinogen, alanine aminotransferase, direct bilirubin, monocyte‐to‐lymphocyte ratio (MLR), and fibrinogen‐to‐albumin ratio (FAR) but decreased levels of lymphocytes, albumin, and high‐density lipoprotein. However, there were no statistically significant differences in the modified Rankin scale (mRS), National Institutes of Health Stroke Scale (NIHSS), and mortality rate between the two groups at discharge. Our study is the first to show the alteration in inflammatory markers but no difference in discharge prognosis between the non‐COVID‐19 and the COVID‐19‐related ischemic stroke patients, during China's COVID‐19 relaxation period. [ABSTRACT FROM AUTHOR]

To clarify the differences between microbial communities resident in disease suppressive soil (DSS) and disease conducive soil (DCS) in tobacco cultivation, representative soil samples were collected from tobacco plantations in Shengjiaba, China, and the structure and diversity of the resident bacterial and fungal communities were analysed using high-throughput sequencing technology. Our results showed a greater number of operational taxonomic units associated with bacteria and fungi in DSS than in DCS. At the phylum level, abundances of Chloroflexi, Saccharibacteria, Firmicutes, and Planctomycetes in DSS were lower than in DCS, but abundance of Gemmatimonadetes was significantly higher. Abundances of Zygomycota and Chytridiomycota were higher in DSS than DCS, but abundance of Rozellomycota was significantly lower. At the genus level, abundances of 18 bacterial and nine fungal genera varied significantly between DSS and DCS. Relative abundances of Acidothermus, Microbacterium, Curtobacterium, and Colletotrichum were higher in DCS than DSS. The Shannon and Chaol indices of DSS microbial communities were higher than those of DCS communities. High microbial diversity reduces the incidence of soil-borne diseases in tobacco plantations and promotes the formation of DSSs. Additional keywords: high-throughput sequencing technology, soil microbial community structure. Received 31 July 2019, accepted 10 September 2019, published online 2 October 2019, Introduction Soil is the most important base material in agricultural production, and the quality of soil can greatly affect the growth and development of crops. Ecological soil deterioration is the [...]

With the development of the smart ocean which contains a large number of wireless sensor nodes, it is a great demand to develop high‐performance marine energy harvesters for powering those sensors. In this work, a highly adaptive hybrid nanogenerator based on triboelectric nanogenerator and electromagnetic generator is proposed. The hybrid nanogenerator can be used for scavenging both wind energy and ocean current energy. The peak power of the hybrid nanogenerator can reach 449.74 mW, which can recharge a 50 mAh‐3.7 V Lithium battery. In addition, it is found that there is a linear relationship between the voltage frequency of the triboelectric nanogenerator and the rotation speed, indicating the hybrid nanogenerator can serve as a flow velocity sensor. A fully self‐powered marine wireless sensor node is fabricated based on the hybrid nanogenerator and management circuit. The demonstrations show that the present hybrid nanogenerator has great potential applications for marine wireless sensing in the scenarios of nearshore, offshore, and underwater. [ABSTRACT FROM AUTHOR]