The building heights of an urban area are useful for space analysis, urban planning, and city management. To this end, a novel method for building height calculation for an urban area is proposed ...based on street view images and a deep learning model, that is, mask region‐based convolutional neural network (Mask R‐CNN). First, a spider of street view maps was developed, and an optimization model for observation locations was designed based on a genetic algorithm, by which the street view images of all buildings can be obtained with the minimum number of downloads. Subsequently, a deep learning workflow was designed based on the Mask R‐CNN to detect buildings from the panorama images. Finally, an accurate height calculation model considering repeated detection of buildings was developed by mapping between detected buildings and actual buildings. Case studies indicate that the mean error of height calculation is 0.78 m, which achieves high precision for calculating building heights in urban areas, while the average calculation time is 4.57 s per building, which indicates that the proposed method is efficient for the application in urban areas.
Display omitted
•The preference order was HAc > HPr > Glu + HAc > Glu in both R40 and R80 systems.•NO2− accumulation and NTR reached up to 67.03 mg/L, 99.14% in the HAc-R80 system.•The PD process of ...Glu was obviously accelerated as HAc was added.•Kinetic analysis revealed the nutrient transformation linked with NO2− accumulation.•Terrimonas, Bacillus, and norank_f_Saprospiraceae dominated HAc and HPr systems.
The combined effects of carbon source (HAc, HPr, Glu, Glu + HAc) and nitrate concentration (40, 80 mg/L labeling as R40, R80) on partial denitrification (PD) were discussed at C/N ratio of 2.5 (COD = 100, 200 mg/L). The optimal NO2−-N and NTR reached to 67.03 mg/L, 99.14% in HAc-R80 system, and denitrification kinetics revealed the same conclusion, corresponding to higher COD utilization rate (CUR: 58.46 mgCOD/(gVSS·h)), nitrate reduction rate (NaRR: 29.94 mgN/(gVSS·h)) and nitrite accumulation rate (NiAR: 29.68 mgN/(gVSS·h)). The preference order was HAc > HPr > Glu + HAc > Glu in both R40 and R80 systems due to different metabolic pathways, however, the NO2−-N accumulation and kinetic parameters of R80 group were dramatically higher than those in R40 for the same carbon source. The R80 group facilitated more concentrated biodiversity (607–808 OTUs) with Terrimonas and norank_f_Saprospiraceae responsible for high NO2−-N accumulation in HAc and HPr served systems, while norank_f_norank_o_Saccharimonadales and OLB13 dominated the Glu containing systems.
The low initial Coulombic efficiency (ICE) and insufficient cycling lives of silicon (Si)‐based anodes seriously hinder their eventual introduction into next‐generation high‐energy‐density ...lithium–ion batteries (LIBs). Herein, an engineering prelithiation binder strategy based on polyacrylic acid (LixPAA) is proposed for representative SiOx anodes. The ICEs and cycling lives of SiOx anodes are significantly improved by precisely controlling the lithiation degree of PAA binder. The ICE of the high‐loading (3.0 mg cm−2) SiOx electrode increases by 10.9% when the Li0.75PAA binder replaces the PAA binder. Moreover, the working mechanism of the lithiation binder strategy to improve the electrochemical performances (especially for ICE) is systematically investigated, which is universally applied to other Si anodes such as Si nanoparticles and Si/graphite. This universal binder strategy and proposed working mechanism provide enlightenment on constructing high‐ICE, high‐energy‐density, and long‐life Si‐based anodes.
Herein, the LixPAA binders with optimal lithiation degrees are proposed for high‐areal‐capacity Si‐based anodes with high ICE. The LixPAA binders stabilize the electrode structure while accelerating the Li transport kinetics of the electrode. The suppression of binder side reactions and the provision of extra Li sources via lithiation are also beneficial to enhance the ICEs of Si‐based anodes.
The large data scale and computational resources required by Convolutional Neural Networks (CNNs) hinder the practical application on mobile devices. However, channel pruning has become one of the ...most efficient methods for addressing this problem, with many existing researches proving its practicability in the field of model compression. The current channel pruning methods mainly start with the perspective of assessing the importance of channels or manual setting of the evaluation criteria, which requires unnecessary human intervention and shows the lack of certain automaticity. In this paper, an effective automatic channel pruning (EACP) method for neural networks is proposed. Specifically, we adopt the k-means++ method to cluster filters with similar features hierarchically in each convolutional layer, forming an initial compact compression structure. Subsequently, we use an improved social group optimization (SGO) algorithm to iteratively search and optimize the compression process of the post-clustered structure to find the optimal compressed structure. The effectiveness of the proposed approach is tested with respect to three leading CNN models on two image classification datasets. In CIFAR-10, our method reduces the FLOPs of GoogLeNet by 58.10 % and improves the accuracy by 0.20 % compared to the baseline.
Display omitted
•The biochar (BC) plus bean dregs (BD) decreased the NH3 and N2O emissions.•BD + BC increased the abundance of AOB amoA gene to decrease the NH3 emission.•The abundance of nirS-type ...denitrifier was more closely associated with N2O.•The nosZ-type gene was the more functional communities to effect the N2O emissions.
In this study, the effect of biochar (BC) and bean dregs (BD) on nitrifiers and denitrifiers as well as the contributions to the NH3 and N2O emissions were investigated. Compared with the BD treatment, the maximum value of NH3 and N2O emission was decreased by 32.92% and 46.61% in the BD + BC treatment, respectively. The production of NH3 and N2O was closely associated with the abundance and structure of nitrogen functional genes. BD + BC increased the abundance of AOB amoA gene to decrease the NH3 emission. The abundance of nirS was more closely associated with N2O. The abundance of nirS in the BD + BC was lowered by 18.93% compared with the BD treatment, thereby decreasing the N2O emission after composting. Besides, the nosZ-type gene was the more functional denitrification bacterial communities to effect the N2O emissions.
Photocatalysis shows a great potential for N2 fixation to NH3 under mild conditions, which intrigues increasing research attention in recent decades. To this end, the design of efficient ...photocatalysts is the key. Herein, we report the synthesis of single atom Ru decorated TiO2 nanosheets rich in oxygen vacancies. Single Ru sites greatly promoted photoreduction of aqueous N2 to NH3, affording an NH3 formation rate of 56.3 μg/h/gcat. We found that isolated Ru atoms likely weakened the hydrogen evolution, promoted absorption of N2, and also improved the charge carrier separation, which led to enhanced N2 photofixation.
We report new searches for solar axions and galactic axionlike dark matter particles, using the first low-background data from the PandaX-II experiment at China Jinping Underground Laboratory, ...corresponding to a total exposure of about 2.7×10^{4} kg day. No solar axion or galactic axionlike dark matter particle candidate has been identified. The upper limit on the axion-electron coupling (g_{Ae}) from the solar flux is found to be about 4.35×10^{-12} in the mass range from 10^{-5} to 1 keV/c^{2} with 90% confidence level, similar to the recent LUX result. We also report a new best limit from the ^{57}Fe deexcitation. On the other hand, the upper limit from the galactic axions is on the order of 10^{-13} in the mass range from 1 to 10 keV/c^{2} with 90% confidence level, slightly improved compared with the LUX.
The lining structures of tunnels are typically constructed using sprayed or cast concrete materials, and their performance and quality during tunnel excavation and blasting are crucial for the ...stability and safety of tunnels. Therefore, the safe distance between the lining structure and blasting source should be determined to avoid concrete damage caused by blasting vibrations. In this study, taking the subway tunnel of Danshan Station in Qingdao as an example, the JH-2 model is introduced as the constitutive model of the tunnel blasting simulation, and the JH-2 model parameters of the local surrounding rock are obtained by experiments, and finally the numerical simulation and theoretical verification are carried out to study the safety distance of shotcrete under various safety judgment standards. The results indicate that the JH-2 model can effectively simulate the propagation of stress waves under different media conditions, and the closer the strength parameters and pressure constant of the lining structure are to those of the surrounding rock, the safer the concrete-rock bonding interface. During tunnel blasting construction using the ring blasting method, the peak particle velocity (PPV) of the lining structure increases with an increase in the arch angle. Based on the numerical simulation results, we recommend that concrete lining be constructed at a distance of at least 62 m from the blasting source to avoid damage caused by vibrations. The effect of concrete tensile failure caused by longitudinal stress is much smaller than the damage to the bonding interface caused by the PPV and can be neglected.
An effective codoping approach is described to modify the photoelectrochemical properties of anatase TiO2 by doping with nonmetal (N or C) and transition metal (Nb or Ta) impurities. Here, ...compensated and noncompensated codoped TiO2 systems are constructed with different proportions and dopant species, and then their dopant formation energies and electronic properties are calculated to study the stability and visible-light photoactivity by first-principles density functional theory incorporating the LDA+U formalism, respectively. The calculated results demonstrate that the codoping with transition metals facilitates the enhancement of the concentration of p-type dopants (N and C) in the host lattice. Especially, both 1:2 compensated Nb/C/Nb and Ta/C/Ta codopings not only reduce the energy gap to enhance the optical absorption and eliminate the local trapping to improve carrier mobility and conversion efficiency but also do not lower the reduction potential of the conduction band edge. Our designated strategies of codoped anatase TiO2 simultaneously meet the criteria for water splitting. It should be pointed out that, to be successful, the proper proportion of transition metal and nonmetal impurities in the host lattice should be controlled so that reasonable photoelectrochemical properties can be achieved.
PDF
