Abstract The statistical model for automatic flow recognition is significant for public place management. However, the current model suffers from insufficient statistical accuracy and low ...lightweight. Therefore, in this study, the structure of the lightweight object detection model "You Only Live Once v3" is optimized, and the "Deep Simple Online Real-Time Tracking" algorithm with the "Person Re-Identification" module is designed, so as to construct a statistical model for people flow recognition. The results showed that the median PersonAP of the designed model was 94.2%, the total detection time was 216 ms, the Rank-1 and Rank-10 were 87.2% and 98.6%, respectively, and the maximum occupied memory of the whole test set was 2.57 MB, which was better than all comparison models. The results indicate that the intelligent identification statistical model for public crowd flow obtained through this design and training has higher statistical accuracy, less computational resource consumption, and faster computing speed. This has certain application space in the management and guidance of crowd flow in public places.
Compared to modern fossil‐fuel‐based refineries, the emerging electrocatalytic refinery (e‐refinery) is a more sustainable and environmentally benign strategy to convert renewable feedstocks and ...energy sources into transportable fuels and value‐added chemicals. A crucial step in conducting e‐refinery processes is the development of appropriate reactions and optimal electrocatalysts for efficient cleavage and formation of chemical bonds. However, compared to well‐studied primary reactions (e.g., O2 reduction, water splitting), the mechanistic aspects and materials design for emerging complex reactions are yet to be settled. To address this challenge, herein, we first present fundamentals of heterogeneous electrocatalysis and some primary reactions, and then implement these to establish the framework of e‐refinery by coupling in situ generated intermediates (integrated reactions) or products (tandem reactions). We also present a set of materials design principles and strategies to efficiently manipulate the reaction intermediates and pathways.
The concept of the electrocatalytic refinery (e‐refinery) is an intrinsically sustainable strategy to convert renewable feedstocks and energy sources to transportable fuels and value‐added chemicals. This Review describes the concept, fundamentals, and framework of e‐refinery processes with some game‐changing reactions and innovative catalyst design strategies.
The hydrogen evolution reaction (HER) is a fundamental process in electrocatalysis and plays an important role in energy conversion for the development of hydrogen‐based energy sources. However, the ...considerably slow rate of the HER in alkaline conditions has hindered advances in water splitting techniques for high‐purity hydrogen production. Differing from well documented acidic HER, the mechanistic aspects of alkaline HER are yet to be settled. A critical appraisal of alkaline HER electrocatalysis is presented, with a special emphasis on the connection between fundamental surface electrochemistry on single‐crystal models and the derived molecular design principle for real‐world electrocatalysts. By presenting some typical examples across theoretical calculations, surface characterization, and electrochemical experiments, we try to address some key ongoing debates to deliver a better understanding of alkaline HER at the atomic level.
Focusing on the long‐lasting debates surrounding the activity descriptor for the electrocatalytic hydrogen evolution reaction in alkaline conditions, some fundamental studies, from theoretical computations and surface electrochemistry on single crystal models, to practical electrocatalysts with large surfaces, are summarized.
Abstract
In today’s society where electric vehicles are widely used, it is particularly important to make electric vehicles more efficient and convenient to charge. Wireless power transfer technology ...is becoming increasingly popular as a new type of charging technology. Different from conventional charging strategies, wireless power transfer becomes a hot topic in industry and academia due to the application possibility. It can not be ignored that this technology can also effectively reduce energy consumption. And the technology contributes to improve some environmental issues. Without doubt that it is a kind of beneficial clean energy source in today’s society. In this paper, the state-of-the-art wireless power transfer technologies are comprehensively review in terms of operation characteristics and optimization strategies. Meanwhile, a comparative analysis is given with different application scenarios, including the cost and power conversion efficiency. At the same time, the future perspectives for developing the wireless power transfer techniques are given.
The electrocatalytic hydrogen‐evolution reaction (HER), as the main step of water splitting and the cornerstone of exploring the mechanism of other multi‐electron transfer electrochemical processes, ...is the subject of extensive studies. A large number of high‐performance electrocatalysts have been developed for HER accompanied by recent significant advances in exploring its electrochemical nature. Herein we present a critical appraisal of both theoretical and experimental studies of HER electrocatalysts with special emphasis on the electronic structure, surface (electro)chemistry, and molecular design. It addresses the importance of correlating theoretical calculations and electrochemical measurements toward better understanding of HER electrocatalysis at the atomic level. Fundamental concepts in the computational quantum chemistry and its relation to experimental electrochemistry are also presented along with some featured examples.
All for HER: A large number of high‐performance electrocatalysts for the hydrogen‐evolution reaction (HER) have been developed. Computational chemistry can direct the molecular design of these catalysts, and electrochemical experiments can be used to verify theoretical predictions.
In the past, the design of efficient electrocatalyst materials for alkaline hydrogen evolution reaction (HER) was mostly focused on tuning the adsorption properties of reaction intermediates. A ...recent breakthrough shows that the performance can be improved by manipulating water structure at the electrode‐electrolyte interface using atomically localized electric fields. The new approach was realized by using IrRu dizygotic single‐atom sites and led to a significantly accelerated water dissociation and an overall improved alkaline HER performance. Supported by extensive data from advanced modeling, characterization, and electrochemical measurements, the work delivers an intricate examination of the interaction between water molecules and the catalyst surface, thereby enriching our understanding of water dissociation kinetics and offering new insights to boost overall alkaline HER efficiency.
Fu, Wang, Zhang, Cortés, Liu and co‐workers validated a new strategy to improve the performance of alkaline hydrogen evolution reaction by introducing localized electric fields and tuning the water structure at the electrode‐electrolyte interface.
Using month‐long daily diary data collected between 2019 and 2020 among 99 dyads of Canadian parents (58.6% White, Mage = 43.5, 69.7% female) and adolescents (51.5% White, Mage = 14.6, 53.5% female) ...from middle to high socioeconomic status families, this study investigated parents' and adolescents' daily shared and unique perceptions of parental psychological control and adolescent emotional problems at within‐ and between‐family level, and examined their cross‐day associations. Multilevel multi‐trait multi‐method confirmatory factor analysis revealed both convergence and divergence across parent–adolescent perceptions at the within level, but no convergence at the between level. Dynamic structural equation modeling revealed cross‐day associations across different perspectives of parenting and adolescent behaviors. Findings contribute novel knowledge to understanding parent–child daily interactions with a multi‐informant approach.
The classical vector autoregressive model is a fundamental tool for multivariate time series analysis. However, it involves too many parameters when the number of time series and lag order are even ...moderately large. This article proposes to rearrange the transition matrices of the model into a tensor form such that the parameter space can be restricted along three directions simultaneously via tensor decomposition. In contrast, the reduced-rank regression method can restrict the parameter space in only one direction. Besides achieving substantial dimension reduction, the proposed model is interpretable from the factor modeling perspective. Moreover, to handle high-dimensional time series, this article considers imposing sparsity on factor matrices to improve the model interpretability and estimation efficiency, which leads to a sparsity-inducing estimator. For the low-dimensional case, we derive asymptotic properties of the proposed least squares estimator and introduce an alternating least squares algorithm. For the high-dimensional case, we establish nonasymptotic properties of the sparsity-inducing estimator and propose an ADMM algorithm for regularized estimation. Simulation experiments and a real data example demonstrate the advantages of the proposed approach over various existing methods.
Supplementary materials
for this article are available online.
Most fundamental studies of electrocatalysis are based on the experimental and simulation results obtained for bulk model materials. Some of these mechanistic understandings are inapplicable for more ...active nanostructured electrocatalysts. Herein, considering the simplest and most typical electrocatalytic process, the hydrogen evolution reaction, an alternative reaction mechanism is proposed for nanomaterials based on the identification of a new intermediate, which differs from those commonly known for the bulk counterparts. In-situ Raman spectroscopy and electrochemical thermal/kinetic measurements were conducted on a series of nanomaterials under different conditions. In high-pH electrolytes with negligible hydronium (H
O
) concentration in bulk phase, massive H
O
intermediates are found generating on the catalytic surface during water dissociation and hydrogen adsorption processes. These H
O
intermediates create a unique acid-like local reaction environment on nanostructured catalytic surfaces and cut the energy barrier of the overall reaction. Such phenomena on nanostructured electrocatalysts explain their widely observed anomalously high activity under high-pH conditions.
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