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It is important to extract both global and local features for view-based 3D shape classification. Therefore, we propose a 3D shape classification method based on global and local features extraction with collaborative learning. This method consists of a patch-level transformer sub-network (PTS) and a view-level transformer sub-network (VTS). In the PTS, a single view is divided into multiple patches. And a multi-layer transformer encoder is employed to accurately highlight discriminative patches and capture correlations among patches in a view, which can efficiently filter out the meaningless information and enhance meaningful information. The PTS can aggregate patch features into a 3D shape representation with rich local details. In the VTS, a multi-layer transformer encoder is employed to assign different attention to each view and obtain the contextual relationship among views, which can highlight the discriminative views among all the views of the same 3D shape and efficiently aggregate view features into a 3D shape representation. A collaborative loss is applied to encourage the two branches to learn collaboratively and teach each other in training. Experiments on two 3D benchmark datasets show that our proposed method outperforms current methods. [ABSTRACT FROM AUTHOR]

In order to reduce by-product nitrite, a more toxic compound than nitrate, and increase high value-added products ammonia in the electrochemical reduction nitrate process, the novel Cu–Co/Ti cathode material was applied in this process. In this paper, the electrochemical process was carried out in a single compartment electrolytic cell, and with Cu–Co/Ti electrode as cathode, identifying the effects of current density, pH, electrolytes in the nitrate reduction, and the distribution of products. The Cu–Co/Ti cathode exhibited 94.65% NO3−-N (nitrate–N) removal, 0.18% NO2−-N (nitrite-N) generation, and 40.86% NH4−-N (ammonia-N) generation with the assistance of Na2SO4 electrolyte in 6 h at 10 mA cm−2 and pH 6. Compared with the Cu/Ti cathode, the higher nitrate removal ratio and lower nitrite generation ratio were obtained on the Cu–Co/Ti cathode. The excellent performance of Cu–Co/Ti cathode is ascribed to the synergy of Cu and Co, which couples the facilitation of nitrate conversion to nitrite and the acceleration of nitrite reduction on the Cu–Co/Ti cathode. The LSV curves showed that nitrate and nitrite might undergo indirect and direct reduction reactions on Cu–Co/Ti cathode. The possible pathways of nitrate reduction on the Cu–Co/Ti cathodes were proposed. These results highlight the viability of using the Cu–Co/Ti cathode developed at this work for the nitrate removal from contaminated waters. This study achieved low-nitrite generation by Cu–Co/Ti cathode during electrochemical nitrate reduction. [ABSTRACT FROM AUTHOR]

Excessive nitrates are among the most concerned pollutants in surface, ground and industrial waters. The development of novel materials and technologies for wastewater treatment from nitrate is an urgent task. The electrocatalytic reduction technology is a friendly environmental and promising technology to remove nitrate. In order to realize the recycling of sewage, the conversion of nitrate into high value-added ammonia by cathode materials is a direction worthy of research. In this paper, the novel Cu–Sn bimetallic cathode was prepared using electrodeposition method to convert nitrate in water to ammonia. The surface morphology, element composition and crystalline structure of the Cu–Sn bimetallic cathode was probed by SEM, EDS and XRD. The experiments of the removal of –N by electrocatalytic reduction on the Cu–Sn cathode were performed in a single compartment electrolytic cell. The results showed that the particles on the surface of Cu–Sn cathode coating were fine and evenly distributed, which was beneficial to catalysis. The mass fraction of Cu and Sn on the surface of Cu–Sn coating was 21.36 and 78.64%. The alloy phases of CuSn and Cu10Sn3 were formed in the coating of the cathode. For the Cu-Sn cathode, the removal ratio of –N was 34.4% and the selective of –N was 100% under the optimum conditions of the current density of 10 mA cm–2 and pH of 10. The nitrate reduction on the Cu–Sn cathode was consistent with the pseudo first-order kinetic equation. Through the analysis of the action mechanism of metal elements and comparison with Cu–Bi cathode, a possible path of nitrate reduction on the Cu–Sn cathode and Cu–Bi cathode was proposed. The obtained results have an important guiding significance for the conversion of the nitrate in wastewater into useful ammonia by electrocatalytic reduction technology. [ABSTRACT FROM AUTHOR]

Electrochemical oxidation of NOR (norfloxacin) was first investigated on Ti/SnO2-Sb, Ti/SnO2-Sb-Ni, and Ti/SnO2-Sb-Mo electrodes prepared by sol-gel method. The influence of transition metal doping on the electrode performance was characterized by SEM (scanning electron microscopy), EDS (energy-dispersive spectrometer), XRD (X-ray diffraction), and LSV (linear voltammetric curve). The doping of metal elements can change the surface morphology of the electrodes and the grain size of the active layer, which affect the electrocatalytic activity of the electrode. Among these three prepared electrodes, the Ti/SnO2-Sb-Ni electrode has the highest oxygen evolution potential and the best removal effect on NOR. The effects of current density, the pH value, and the initial concentration of NOR on the removal of NOR by electrochemical oxidation with Ti/SnO2-Sb-Ni electrode were investigated. For Ti/SnO2-Sb-Ni electrode, the removal rate of NOR was 100% after 30 min and the removal rate of TOC was 75% after 120 min under the conditions of the current density of 20 mA cm−2, pH of 3, initial concentration of NOR of 100 mg L−1, and concentration of Na2SO4 of 0.25 mol L−1. The kinetic investigation showed that the oxidation of NOR on these three electrodes displayed pseudo-first-order kinetic behavior. For NOR degradation, the electrocatalytic performance of p-type metal-doped Ti/SnO2-Sb electrode (Ti/SnO2-Sb-Ni) is better than that of n-type metal-doped Ti/SnO2-sb electrode (Ti/SnO2-Sb-Mo). [ABSTRACT FROM AUTHOR]

The traditional lifting wavelet transform cannot effectively reconstruct the nonhorizontal and nonvertical high-frequency information of an image. In this paper, we present a new image compression method based on adaptive directional prediction discrete wavelet transform (ADP-DWT). We first design a directional prediction model to obtain the optimal transform direction of the lifting wavelet. Then, we execute the directional lifting transform along the optimal transform direction. The edge and texture energy can be reduced in the nonhorizontal and nonvertical directions of the high-frequency sub-bands. Finally, the wavelet coefficients are coded with the set partitioning in hierarchical trees (SPIHT) algorithm. The new method holds the advantages of both adaptive directional lifting (ADL) and direction-adaptive discrete wavelet transform (DA-DWT), and the computational complexity is far lower than that in these methods. For the images containing regular and fine textures or edges, the coding preformance of ADP-DWT is better than that of ADL and DA-DWT. [ABSTRACT FROM AUTHOR]