12,715 research outputs found
Evaluation of the pore morphologies for piezoelectric energy harvesting application
Piezoelectric energy harvesting has attracted significant attention in recent years due to their high-power density and potential applications for self-powered sensor networks. In comparison to dense piezoelectric ceramics, porous piezoelectric ceramics exhibit superiority due to an enhancement of piezoelectric energy harvesting figure of merit. This paper provides a detailed examination of the effect of pore morphology on the piezoelectric energy harvesting performance of porous barium calcium zirconate titanate 0.5Ba(Zr0.2 Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BCZT) ceramics. Three different pore morphologies of spherical, elliptical, and aligned lamellar pores were created via the burnt-out polymer spheres method and freeze casting. The relative permittivity decreased with increasing porosity volume fraction for all porous BCZT ceramics. Both experimental and simulation results demonstrate that porous BCZT ceramics with aligned lamellar pores exhibit a higher remanent polarization. The longitudinal d33 piezoelectric charge coefficient decreased with increasing porosity volume fraction for the porous ceramics with three different pore morphologies; however, the rate of decrease in d33 with porosity is slower for aligned lamellar pores, leading to the highest piezoelectric energy harvesting figure of merit. Moreover, the peak power density of porous BCZT ceramics with aligned lamellar pores is shown to reach up to 38 μW cm-2 when used as an energy harvester, which is significantly higher than that of porous BCZT ceramics with spherical or elliptical pores. This work is beneficial for the design and manufacture of porous ferroelectric materials in devices for piezoelectric energy harvesting applications.</p
New Developments in Aromatic Halogenation, Borylation, and Cyanation
Several green procedures have been developed for synthesizing functionalized aromatics: i) AuCl3-catalyzed halogenation of aromatic compounds, including aryl boronates; ii) Fe2O3-catalyzed direct aromatic C–H bond borylation; iii) Pd-catalyzed
direct cyanation of indoles; iv) direct conversion of arylamines to pinacol boronates
SST: Real-time End-to-end Monocular 3D Reconstruction via Sparse Spatial-Temporal Guidance
Real-time monocular 3D reconstruction is a challenging problem that remains
unsolved. Although recent end-to-end methods have demonstrated promising
results, tiny structures and geometric boundaries are hardly captured due to
their insufficient supervision neglecting spatial details and oversimplified
feature fusion ignoring temporal cues. To address the problems, we propose an
end-to-end 3D reconstruction network SST, which utilizes Sparse estimated
points from visual SLAM system as additional Spatial guidance and fuses
Temporal features via a novel cross-modal attention mechanism, achieving more
detailed reconstruction results. We propose a Local Spatial-Temporal Fusion
module to exploit more informative spatial-temporal cues from multi-view color
information and sparse priors, as well a Global Spatial-Temporal Fusion module
to refine the local TSDF volumes with the world-frame model from coarse to
fine. Extensive experiments on ScanNet and 7-Scenes demonstrate that SST
outperforms all state-of-the-art competitors, whilst keeping a high inference
speed at 59 FPS, enabling real-world applications with real-time requirements
Nuclear Factor-Kappa B Activity Regulates Brain Expression of P-Glycoprotein in the Kainic Acid-Induced Seizure Rats
This study was aimed to investigate the effect of NF-κB activity on the seizure susceptibility, brain damage, and P-gp expression in kainic acid- (KA-) induced seizure rats. Male SD rats were divided into saline control group (NS group), KA induced epilepsy group (EP group), and epilepsy group intervened with NF-κB inhibitor-pyrrolidine dithiocarbamate salt (PDTC group) or with dexamethasone (DEX group). No seizures were observed in the rats of NS group. Compared with NS group, increased P-gp expression and NF-κB activation in the rat brain of the EP group were observed after KA micro-injection. Both PDTC and DEX pre-treatment significantly increased the latency to grade III or V seizure onset compared to EP group but failed to show neuron-protective effect as the number of survival neurons didn't significantly differ from that in EP group. Furthermore, PDTC pre-treatment significantly decreased P-gp expression along with NF-κB activation in the hippocampus CA3 area and amygdala complex of rats compared with the EP group, implying that NF-κB activation involved in the seizure susceptibility and seizure induced brain P-gp over-expression. Additionally, DEX pre-treatment only decreased P-gp expression level without inhibition of NF-κB activation, suggesting NF-κB independent pathway may also participate in regulating seizure induced P-gp over-expression
- …