Non-local affinity adaptive acceleration propagation network for generating dense depth maps from LiDAR.

Depth completion aims to generate dense depth maps from the sparse depth images generated by LiDAR. In this paper, we propose a non-local affinity adaptive accelerated (NL-3A) propagation network for depth completion to solve the mixing depth problem of different objects on the depth boundary. In the network, we design the NL-3A prediction layer to predict the initial dense depth maps and their reliability, non-local neighbors and affinities of each pixel, and learnable normalization factors. Compared with the traditional fixed-neighbor affinity refinement scheme, the non-local neighbors predicted by the network can overcome the propagation error problem of mixed depth objects. Subsequently, we combine the learnable normalized propagation of non-local neighbor affinity with pixel depth reliability in the NL-3A propagation layer, so that it can adaptively adjust the propagation weight of each neighbor during the propagation process, which enhances the robustness of the network. Finally, we design an accelerated propagation model. This model enables parallel propagation of all neighbor affinities and improves the efficiency of refining dense depth maps. Experiments on KITTI depth completion and NYU Depth V2 datasets show that our network is superior to most algorithms in terms of accuracy and efficiency of depth completion. In particular, we predict and reconstruct more smoothly and consistently at the pixel edges of different objects.

Unsupervised Depth Completion Guided by Visual Inertial System and Confidence.

This paper solves the problem of depth completion learning from sparse depth maps and RGB images. Specifically, a real-time unsupervised depth completion method in dynamic scenes guided by visual inertial system and confidence is described. The problems such as occlusion (dynamic scenes), limited computational resources and unlabeled training samples can be better solved in our method. The core of our method is a new compact network, which uses images, pose and confidence guidance to perform depth completion. Since visual-inertial information is considered as the only source of supervision, the loss function of confidence guidance is creatively designed. Especially for the problem of pixel mismatch caused by object motion and occlusion in dynamic scenes, we divide the images into static, dynamic and occluded regions, and design loss functions to match each region. Our experimental results in dynamic datasets and real dynamic scenes show that this regularization alone is sufficient to train depth completion models. Our depth completion network exceeds the accuracy achieved in prior work for unsupervised depth completion, and only requires a small number of parameters.

City Health Examination and Evaluation of Territory Spatial Planning for SDG11 in China: A Case Study of Xining City in Qinghai Province.

City health examination and evaluation of territorial spatial planning is a new policy tool in China. However, research on city health examination and evaluation of territorial spatial planning is still in the exploratory stage in China. Guided by sustainable cities and communities (SDG11), a reasonable city health examination and evaluation index system for Xining City in Qinghai Province is constructed in this paper. The improved technique for order preference by similarity to ideal solution (TOPSIS) was used to quantify the evaluation results, and the city health index was visualized using the city health examination signals and warning panel. The results show that the city health index of Xining City continuously rose from 35.76 in 2018 to 69.76 in 2020. However, it is still necessary to address the shortcomings in innovation, coordination, openness and sharing and to improve the level of city space governance in a holistic way. This study is an exploration of the methodology used in city health examination and the evaluation of territorial spatial planning in China, which can provide a foundation for the sustainable development of Xining City and also provide a case reference for other cities seeking to carry out city health examinations and evaluations of territorial spatial planning in China.

Nano-silica anti-icing coatings for protecting wind-power turbine fan blades.

Wind power is a promising electricity source. Nevertheless, wind turbine blade icing can cause severe problems in turbine operation. In this study, SiO2 spherical nanoparticles (∼90 nm), produced by RF (radio frequency) plasma spheroidization, were mixed with E51, PDMS, and ethyl acetate, and sprayed on the surface of aluminum plates and regular power windmill fan blades which were already coated with polyurethane primer. XPS and IR spectroscopies revealed the development of SiC and SiPh (Ph = phenolic ring) bonds, whose formation should be favored by the ultrasound and curing processes at 50 °C. The integrity of the coating/substrate interface, whose strength is ascribed to hydrogen bonds, was maintained after 100 icing-melting cycles. The coatings display superhydrophobic behavior and excellent anti-icing performance, along with stability in abrasion, sunlight and self-cleaning ability towards solid pollutants.

Electrocatalysis of formic acid on palladium and platinum surfaces: from fundamental mechanisms to fuel cell applications.

Formic acid as a natural biomass and a CO2 reduction product has attracted considerable interest in renewable energy exploitation, serving as both a promising candidate for chemical hydrogen storage material and a direct fuel for low temperature liquid fed fuel cells. In addition to its chemical dehydrogenation, formic acid oxidation (FAO) is a model reaction in the study of electrocatalysis of C1 molecules and the anode reaction in direct formic acid fuel cells (DFAFCs). Thanks to a deeper mechanistic understanding of FAO on Pt and Pd surfaces brought about by recent advances in the fundamental investigations, the "synthesis-by-design" concept has become a mainstream idea to attain high-performance Pt- and Pd-based nanocatalysts. As a result, a large number of efficient nanocatalysts have been obtained through different synthesis strategies by tailoring geometric and electronic structures of the two primary catalytic metals. In this paper, we provide a brief overview of recent progress in the mechanistic studies of FAO, the synthesis of novel Pd- and Pt-based nanocatalysts as well as their practical applications in DFAFCs with a focus on discussing studies significantly contributing to these areas in the past five years.

Infrared spectroelectrochemical study of dissociation and oxidation of methanol at a palladium electrode in alkaline solution.

The dissociative adsorption and electrooxidation of CH(3)OH at a Pd electrode in alkaline solution are investigated by using in situ infrared spectroscopy with both internal and external reflection modes. The former (ATR-SEIRAS) has a higher sensitivity of detecting surface species, and the latter (IRAS) can easily detect dissolved species trapped in a thin-layer-structured electrolyte. Real-time ATR-SEIRAS measurement indicates that CH(3)OH dissociates to CO(ad) species at a Pd electrode accompanied by a "dip" at open circuit potential, whereas deuterium-replaced CH(3)OH doesn't, suggesting that the breaking of the C-H bond is the rate-limiting step for the dissociative adsorption of CH(3)OH. Potential-dependent ATR-SEIRAS and IRAS measurements indicate that CH(3)OH is electrooxidized to formate and/or (bi)carbonate, the relative concentrations of which depend on the potential applied. Specifically, at potentials negative of ca. -0.15 V (vs Ag/AgCl), formate is the predominant product and (bi)carbonate (or CO(2) in the thin-layer structure of IRAS) is more favorable at potentials from -0.15 to 0.10 V. Further oxidation of the CO(ad) intermediate species arising from CH(3)OH dissociation is involved in forming (bi)carbonate at potentials above -0.15 V. Although the partial transformation from interfacial formate to (bi)carbonate may be justified, no bridge-bonded formate species can be detected over the potential range under investigation.

Palladium nanocrystals bound by {110} or {100} facets: from one pot synthesis to electrochemistry.

A facile one-pot tactic is developed for the selective synthesis of either rhombic dodecahedral or cubic Pd nanocrystals with high yields. By applying a mild cleaning process, we establish for the first time reasonable and distinct electrochemical features corresponding to {110} or {100} facet predominated Pd nanocrystals.

Facile synthesis of Ag@Pd satellites-Fe3O4 core nanocomposites as efficient and reusable hydrogenation catalysts.

Well-dispersed Ag@Pd supported on magnetite nanoparticles have been obtained through a simple colloidal impregnation method. The as-synthesised nanocomposite exhibits greatly enhanced catalytic reactivity and reusability towards 4-nitrophenol hydrogenation.

From HCOOH to CO at Pd electrodes: a surface-enhanced infrared spectroscopy study.

The decomposition of HCOOH on Pd surfaces over a potential range of practical relevance to hydrogen production and fuel cell anode operation was probed by combining high-sensitivity in situ surface-enhanced IR spectroscopy with attenuated total reflection and thin-layer flow cell configurations. For the first time, concrete spectral evidence of CO(ad) formation has been obtained, and a new main pathway from HCOOH to CO(ad) involving the reduction of the dehydrogenation product of HCOOH (i.e., CO(2)) is proposed.

Facile fabrication of ultrafine copper nanoparticles in organic solvent.

A facile chemical reduction method has been developed to fabricate ultrafine copper nanoparticles whose sizes can be controlled down to ca. 1 nm by using poly(N-vinylpyrrolidone) (PVP) as the stabilizer and sodium borohyrdride as the reducing agent in an alkaline ethylene glycol (EG) solvent. Transmission electron microscopy (TEM) results and UV-vis absorption spectra demonstrated that the as-prepared particles were well monodispersed, mostly composed of pure metallic Cu nanocrystals and extremely stable over extended period of simply sealed storage.