264 research outputs found
OPTIMIZATION AND APPLICATION OF HIGHER MATHEMATICS TEACHING BASED ON STUDENTS\u27 SPONTANEOUS INTEREST STRATEGY
Self-supervised phase unwrapping in fringe projection profilometry
Fast-speed and high-accuracy three-dimensional (3D) shape measurement has
been the goal all along in fringe projection profilometry (FPP). The
dual-frequency temporal phase unwrapping method (DF-TPU) is one of the
prominent technologies to achieve this goal. However, the period number of the
high-frequency pattern of existing DF-TPU approaches is usually limited by the
inevitable phase errors, setting a limit to measurement accuracy.
Deep-learning-based phase unwrapping methods for single-camera FPP usually
require labeled data for training. In this letter, a novel self-supervised
phase unwrapping method for single-camera FPP systems is proposed. The trained
network can retrieve the absolute fringe order from one phase map of 64-period
and overperform DF-TPU approaches in terms of depth accuracy. Experimental
results demonstrate the validation of the proposed method on real scenes of
motion blur, isolated objects, low reflectivity, and phase discontinuity
Spatial origin analysis on atmospheric bulk deposition of polycyclic aromatic hydrocarbons in Shanghai
Atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) onto soil threatens terrestrial ecosystem. To locate potential source areas geographically, a total of 139 atmospheric bulk deposition samples were collected during 2012â2019 at eight sites in Shanghai and its surrounding areas. A multisite joint location method was developed for the first time to locate potential source areas of atmospheric PAHs based on an enhanced three dimensional concentration weighted trajectory model. The method considered spatial and temporal variations of atmospheric boundary layer height and homogenized all results over the eight sites via geometric mean. Regional transport was an important contributor of PAH atmospheric deposition while massive local emissions may disturb the identification of potential source areas. Northwesterly winds were associated with elevated deposition fluxes. Potential source areas were identified by the multisite joint location method and included Hebei, Tianjin, Shandong and Jiangsu to the north, and Anhui to the west of Shanghai. PM and SO2 data from the national ground monitoring stations confirmed the identified source areas of deposited PAHs in Shanghai
Nanofluid impact on fluid interaction and migration characteristics for enhanced oil recovery in Baikouquan tight glutenite
Nanofluids have broad prospects in enhancing the oil recovery of reservoirs with low porosity, low permeability, high capillary pressure and low oil recovery. However, the modification effects of nanofluids on tight glutenite reservoirs remain unknown. In this paper, nanofluids with different proportions of silica nanoparticles and sodium dodecyl sulfate were prepared and characterized by zeta potential and particle size distribution. Then, the effects of nanofluids on interfacial tension and reservoir wettability were examined. Next, a computational fluid dynamics method was adopted to further investigate the effects of nanofluids and injection pressure on enhancing oil recovery of the Baikouquan Formation at the pore scale. The experimental results showed that all prepared nanofluids are stable systems with uniform dispersion. The interfacial tension between the nanofluids and oil was reduced by up to 8.01% compared with water, and the reservoir wettability was changed from intermediate-wet to strong hydrophilicity. The simulation results revealed that the water and nanofluid flooding processes could be divided into two stages: the initial channel establishment stage and the channel expansion stage. In the initial stage, the nanofluids hardly showed an enhanced oil recovery effect due to the faster and sharper migration fronts. In the channel expansion stage, the nanofluids clearly showed an enhanced oil recovery effect, as the nanofluids could displace the oil in the relative dead pores during water flooding. After 10 pore volume injection of displacement fluid at an injection pressure of 1 MPa, the oil recovery using NF5 was highest at 76.58%. In addition, a higher injection pressure led to the extraction of relative dead oil at a lower injection pressure near the inlet with a smaller sweep area near the outlet; the effect on recovery has both advantages and disadvantages.Document Type: Original articleCited as: Cao, X., Li, Q., Myers, M., Xu, L., Chen, Q., Tan, Y. Nanofluid impact on fluid interaction and migration characteristics for enhanced oil recovery in Baikouquan tight glutenite. Advances in Geo-Energy Research, 2023, 9(2): 94-105. https://doi.org/10.46690/ager.2023.08.0
Efficacy and Safety of Clearing Heat and Detoxifying Injection in the Treatment of Influenza: A Randomized, Double-Blinded, Placebo-Controlled Trial
Objective. To evaluate the efficacy and safety of CHDI in the treatment of influenza infection. Method. A randomized double-blind, double dummy trial was conducted. Influenza patients with a positive influenza A rapid test diagnosis were randomized to receive CHDI or oseltamivir. Primary outcome was assessed by the median fever alleviation time and clearance time, and secondary outcome was total scores of influenza symptoms. Results. One hundred thirty-nine participants were screened and 34 had a RT-PCR laboratory confirmation of influenza virus infection. Fever alleviation time was 2.5 and 5 hours in CHDI and oseltamivir, respectively, and fever clearance time was 32.5 and 49 hours. The HR of fever alleviation and clearance time shows no significant difference between two groups. Total scores of influenza symptoms descended significantly in both groups after treatment and descended more in CHDI than oseltamivir on day 2. Similar to total symptoms severity score, fever severity score descend more significantly in CHDI than oseltamivir on day 2, and there were no differences on other symptoms. Conclusions. CHDI have a similar effect to oseltamivir in reducing the duration of influenza illness. CHDI was well tolerated, with no serious adverse events noted during the study period
Phyllanthus emblica aqueous extract retards hepatic steatosis and fibrosis in NAFLD mice in association with the reshaping of intestinal microecology
Accumulating evidence suggests that dysregulation of the intestinal flora potentially contributes to the occurrence and development of nonalcoholic fatty liver disease (NAFLD). Phyllanthus emblica (PE), an edible and medicinal natural resource, exerts excellent effects on ameliorating NAFLD, but the potential mechanism remains unclear. In the present study, a mouse NAFLD model was established by administering a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD). The protective effects of the aqueous extract of PE (AEPE) on the gut microbiota and fecal metabolites in NAFLD mice were detected by performing 16S rRNA gene sequencing and untargeted metabolomics. The administration of middle- and high-dose AEPE decreased the levels of ALT, AST, LDL-C, TG, and Hyp and increased HDL-C levels in CDAHFD-fed mice. Hematoxylinâeosin (H&E), Oil Red O, and Massonâs trichrome staining indicated that AEPE treatment attenuated hepatic steatosis and fibrotic lesions. Moreover, the disordered intestinal microflora was remodeled by AEPE, including decreases in the abundance of Peptostreptococcaceae, Faecalibaculum, and Romboutsia. The untargeted metabolomics analysis showed that AEPE restored the disturbed glutathione metabolism, tryptophan metabolism, taurine and hypotaurine metabolism, and primary bile acid biosynthesis of the gut bacterial community in NAFLD mice, which strongly correlated with hepatic steatosis and fibrosis. Collectively, AEPE potentially ameliorates NAFLD induced by a CDAHFD through a mechanism associated with its modulatory effects on the gut microbiota and microbial metabolism
Preparation and electrochemical properties of pomegranate-shaped FeâOâ/C anodes for li-ion batteries
Due to the severe volume expansion and poor cycle stability, transition metal oxide anode is still not meeting the commercial utilization. We herein demonstrate the synthetic method of core-shell pomegranate-shaped Fe2O3/C nano-composite via one-step hydrothermal process for the first time. The electrochemical performances were measured as anode material for Li-ion batteries. It exhibits excellent cycling performance, which sustains 705 mAh g-1 reversible capacities after 100 cycles at 100 mA g-1. The anodes also showed good rate stability with discharge capacities of 480 mAh g-1 when cycling at a rate of 2000 mA g-1. The excellent Li storage properties can be attributed to the unique core-shell pomegranate structure, which can not only ensure good electrical conductivity for active Fe2O3, but also accommodate huge volume change during cycles as well as facilitate the fast diffusion of Li ion
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