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Aiming at the low precision of Kalman filter in dealing with non-linear and non-Gaussian models and the serious particle degradation in standard particle filter, a zero-velocity correction algorithm of adaptive particle filter is proposed in this paper. In order to improve the efficiency of resampling, the adaptive threshold is combined with particle filter. In the process of resampling, the degradation co-efficient is introduced to judge the degree of particle degradation, and the particles are re-sampled to ensure the diversity of particles. In order to verify the effectiveness and feasibility of the proposed algorithm, a hardware platform based on the inertial measurement unit (IMU) is built, and the state space model of the system is established by using the data collected by IMU, and experiments are carried out. The experimental results show that, compared with Kalman filter and classical particle filter, the positioning accuracy of adaptive particle filter in zero-velocity range is improved by 40.6% and 19.4% respectively. The adaptive particle filter (APF) can correct navigation errors better and improve pedestrian trajectory accuracy.

Organic–inorganic hybrid polysulfone (PSF)-titanium dioxide (TiO2) hollow fiber ultrafiltration (UF) membranes were prepared by sol–gel process and dry–wet spinning method. The effects of added TiO2 nanoparticles on membranes properties and morphologies were investigated by SEM, FT-IR, DSC, contact angle goniometer, UF experiments and so on. The results show that the membrane is a double-row finger-like pore structure, and with the increase of TiO2 content, the volume of finger-like pores increases first and then decreases. The organic–inorganic network structure forms between the TiO2 nanoparticles and the PSF chain introduced by the sol–gel method leads to an increase in the porosity, mechanical strength and thermal stability of the membrane. The addition of TiO2 improves the hydrophilicity, permeability and anti-fouling properties of the membrane. However, high TiO2 concentration induces nanoparticles aggregate, resulting in the decline of hydrophilicity, permeability and anti-fouling properties. So added the right amount of TiO2 nanoparticles can give the membrane better UF performance, mechanical properties and antifouling properties as well as longer service life.

The Foot-mounted Inertial Pedestrian-Positioning System (FIPPS) based on the Micro-Inertial Measurement Unit (MIMU) is a good choice for the forest fire fighters when the Global Navigation Satellite System is unavailable. Zero Velocity Update (ZUPT) provides a solution for reducing cumulative positioning errors caused by the integral calculation of the inertial navigation. However, the performance of ZUPT is highly affected by the low accuracy and high noise of the MIMU. The accuracy of conventional ZUPT for attitude alignment is reduced by the zero offset of acceleration and the drift of a gyroscope during the standing phase. An initial alignment algorithm based on Adaptive Gradient Descent Algorithm (AGDA) is proposed. In the stepping phase, the extended Kalman filter (EKF) is often used to correct attitude and position in track estimation. However, the measurement noise of the EKF is influenced by the high-frequency acceleration and angular velocity. Thus, the accuracy of the attitude and position will decrease. A double-constrained extended Kalman filtering (DEKF) is proposed. An adaptive parameter positively correlated with the acceleration and angular velocity is set, and the measurement noise in the DEKF is adaptively adjusted. The performance of the proposed method is verified by implementing the pedestrian test trajectory using MPU-9150 MIMU manufactured by InvenSense. The results show that the attitude error of the AGDA is 33.82% less than that of the conventional GDA. The attitude error of DEKF is 21.70% less than that of the conventional EKF. The experimental results verify the effectiveness and applicability of the proposed method.

Although planar asymmetric supercapacitors (ASCs) have attracted extensive attentions as prospective microscale energy storage devices, their practical applications are severely confined by the low energy density and inefficient patterning techniques. Herein, poly (3,4-ethylenedioxythiophene) (PEDOT) coated manganese dioxide (MnO2) nanospheres (MnO2@PEDOT) as cathode is firstly fabricated by electrodepositing. Benefitting from the synergistic effect of the nanocomposites, MnO2@PEDOT cathode displays a broad operating voltage from 0 to 1.0 V (vs Ag/AgCl), excellent areal specific capacitance (116.9 mF cm−2 at 0.1 mA cm−2) with outstanding rate capability and cyclic stability. To complement the wide potential of planar ASCs, urchin-like vanadium pentoxide (V2O5) is similarly fabricated as anode with superb electrochemical performance. As a result, the as-assembled V2O5//MnO2@PEDOT planar ASCs show superior characteristics including a stable operating voltage of 1.8 V, commendable energy density of 15.1 μWh cm−2 along with remarkable cycle performance (87.2% retention after 10 000 cycles), and distinguished integrated performance with commercial solar cells, which exceed majority of formerly reported analogous works. Therefore, this work will create new opportunities for high-performance pseudocapacitive planar ASCs to meet the power requirements in wearable and integrated systems.