The component-activity interrelationship of cobalt-based bifunctional electrocatalysts for overall water splitting:Strategies and performance

Cobalt-based electrocatalysts take advantage of potentially harmonizable microstructure and flexible coupling effects compared to commercial noble metal-based catalytic materials.However,conventional water electrolysis systems based on cobalt-based monofunctional hydrogen evolution reaction(HER)or oxygen evolution reaction(OER)catalysts have certain shortcomings in terms of resource utilization and universality.In contrast,cobalt-based bifunctional catalysts(CBCs)have attracted much attention in recent years for overall water splitting systems because of their practicality and reduced preparation cost of electrolyzer.This review aims to address the latest development in CBCs for total hydrolysis.The main modification strategies of CBCs are systematically classified in water electrolysis to provide an overview of how to regulate their morphology and electronic configuration.Then,the catalytic performance of CBCs in total-hydrolysis is summarized according to the types of cobalt-based phosphides,sulfides and oxides,and the mechanism of strengthened electrocatalytic ability is emphasized through combining experiments and theoretical calculations.Future efforts are finally suggested to focus on exploring the dynamic conversion of reaction intermediates and building near-industrial CBCs,designing advanced CBC materials through micro-modulation,and addressing commercial applications.

Recent advances of transition-metal metaphosphates for efficient electrocatalytic water splitting

Sustainable production of H2 through electrochemical water splitting is of great importance in the foreseeable future.Transition-metal metaphosphates(TMMPs)have a three-dimensional(3D)open-framework structure and a high content of P(which exists as PO3-),and therefore have been recognized as highly efficient catalysts for oxygen evolution reaction(OER)and the bottleneck of electrochemical water splitting.Furthermore,TMMPs can also contribute to hydrogen evolution reaction(HER)in alkaline and neutral media by facilitating water dissociation,and thus,overall water splitting can be achieved using this kind of material.In this timely review,we summarize the recent advances in the synthesis of TMMPs and their applications in OER and HER.We present a brief introduction of the structure and synthetic strategies of TMMPs in the first two parts.Then,we review the latest progress made in research on TMMPs as OER,HER,and overall water-splitting electrocatalysts.In this part,the intrinsic activity of TMMPs as well as the current strategy for improving the catalytic activity will be discussed systematically.Finally,we present the future opportunities and the remaining challenges for the application of TMMPs in the electrocatalysis field.

Skeleton Split Strategies for Spatial Temporal Graph Convolution Networks

Action recognition has been recognized as an activity in which individuals’behaviour can be observed.Assembling profiles of regular activities such as activities of daily living can support identifying trends in the data during critical events.A skeleton representation of the human body has been proven to be effective for this task.The skeletons are presented in graphs form-like.However,the topology of a graph is not structured like Euclideanbased data.Therefore,a new set of methods to perform the convolution operation upon the skeleton graph is proposed.Our proposal is based on the Spatial Temporal-Graph Convolutional Network(ST-GCN)framework.In this study,we proposed an improved set of label mapping methods for the ST-GCN framework.We introduce three split techniques(full distance split,connection split,and index split)as an alternative approach for the convolution operation.The experiments presented in this study have been trained using two benchmark datasets:NTU-RGB+D and Kinetics to evaluate the performance.Our results indicate that our split techniques outperform the previous partition strategies and aremore stable during training without using the edge importance weighting additional training parameter.Therefore,our proposal can provide a more realistic solution for real-time applications centred on daily living recognition systems activities for indoor environments.

Recent advances in elaborate interface regulation of BiVO_(4)photoanode for photoelectrochemical water splitting

Bismuth vanadate(BiVO_(4))is an excellent photoanode material for photoelectrochemical(PEC)water splitting system,possessing high theoretical photoelectrocatalytic conversion efficiency.However,the actual PEC activity and stability of BiVO_(4)are faced with great challenges due to factors such as severe charge recombination and slow water oxidation kinetics at the interface.Therefore,various interface regulation strategies have been adopted to optimize the BiVO_(4)photoanode.This review provides an in-depth analysis for the mechanism of interface regulation strategies from the perspective of factors affecting the PEC performance of BiVO_(4)photoanodes.These interface regulation strategies improve the PEC performance of BiVO_(4)photoanode by promoting charge separation and transfer,accelerating interfacial reaction kinetics,and enhancing stability.The research on the interface regulation strategies of BiVO_(4)photoanode is of great significance for promoting the development of PEC water splitting technology.At the same time,it also has inspiration for providing new ideas and methods for designing and preparing efficient and stable catalytic materials.

Modeling and Solving Lot-Splitting Scheduling Problem Based on Process

In flexible job-shop batch scheduling problem, the optimal lot-size of different process is not always the same because of different processing time and set-up time. Even for the same process of the same workpiece, the choice of machine also affects the optimal lot-size. In addition, different choices of lot-size between the constrained processes will impact the manufacture efficiency. Considering that each process has its own appropriate lot-size, we put forward the concept of scheduling with lot-splitting based on process and set up the scheduling model of lot-splitting to critical path process as the core. The model could update the set of batch process and machine selection strategy dynamically to determine processing route and arrange proper lot-size for different processes, to achieve the purpose of optimizing the makespan and reducing the processing batches effectively. The experiment results show that, comparing with lot-splitting scheduling scheme based on workpiece, this model optimizes the makespan and improves the utilization efficiency of the machine. It also greatly decreases the machined batches （42%） and reduces the complexity of shop scheduling production management.

Review of the development of power system out-of-step splitting control and some thoughts on the impact of large-scale access of renewable energy

Out-of-step oscillation is a very destructive physical phenomenon in power system, which could directly cause big blackout accompanied by serious sociology-economic impacts. Out-of-step splitting control is an indispensable means, which could protect the system from major shocks of out-of-step oscillation. After years of development, it has achieved certain amount of research results. Have the existing methods been able to meet the requirements of out-of-step splitting? What improvements are needed? Under this background, this review is written. It combs the development of out-of-step splitting control technologies and analyzes the technical routes and characteristics of different methods. It points out the contradiction between rapidity and optimality is the biggest technical problem, existing in both the traditional local measurement based out-of-step splitting protection and the wide-area information based out-of-step splitting protection. It further points out that the advantages of the two types of protections can be combined with the unique physical characteristics of the out-of-step center to form a more advantageous splitting strategy. Besides, facing the fact of large-scale renewable energy access to power grid in recent years, this review also analyzes the challenges brought by it and provides some corresponding suggestions. It is hoped to provide some guidance for the subsequent research work.

Growth and nitrogen productivity of drip-irrigated winter wheat under different nitrogen fertigation strategies in the North China Plain

Excessive application of nitrogen (N) fertilizer is the main cause of N loss and poor use efficiency in winter wheat (Triticum aestivum L.) production in the North China Plain (NCP).Drip fertigation is considered to be an effective method for improving N use efficiency and reducing losses,while the performance of drip fertigation in winter wheat is limited by poor N scheduling.A two-year field experiment was conducted to evaluate the growth,development and yield of drip-fertigated winter wheat under different split urea (46%N,240 kg ha^(-1)) applications.The six treatments consisted of five fertigation N application scheduling programs and one slow-release fertilizer (SRF) application.The five N scheduling treatments were N0–100 (0%at sowing and 100%at jointing/booting),N25–75 (25%at sowing and 75%at jointing and booting),N50–50(50%at sowing and 50%at jointing/booting),N75–25 (75%at sowing and 25 at jointing/booting),and N100–0 (100%at sowing and 0%at jointing/booting).The SRF (43%N,240 kg ha^(-1)) was only used as fertilizer at sowing.Split N application significantly (P<0.05) affected wheat grain yield,yield components,aboveground biomass (ABM),water use efficiency(WUE) and nitrogen partial factor productivity (NPFP).The N50–50 and SRF treatments respectively had the highest yield(8.84 and 8.85 t ha^(-1)),ABM (20.67 and 20.83 t ha^(-1)),WUE (2.28 and 2.17 kg m^(-3)) and NPFP (36.82 and 36.88 kg kg^(-1)).This work provided substantial evidence that urea-N applied in equal splits between basal and topdressing doses compete economically with the highly expensive SRF for fertilization of winter wheat crops.Although the single-dose SRF could reduce labor costs involved with the traditional method of manual spreading,the drip fertigation system used in this study with the N50–50 treatment provides an option for farmers to maintain wheat production in the NCP.

Typical strategies to facilitate charge transfer for enhanced oxygen evolution reaction: Case studies on hematite

Hydrogen can be sustainably produced through photoelectrochemical(PEC)water splitting.The process of PEC water splitting is composed of two vital half-reactions:water oxidation to O2 on photoanode,and proton reduction to H2 on photocathode.Both in thermodynamics and kinetics,the oxidation of water on photoanode is much more challenging,because the formation of O2 involves the four-holes reaction process that is more difficult than the two-protons reduction.Accordingly,the oxidation of water into O2 is the rate-determining reaction for PEC water splitting,which is closely affected by the light harvesting,charge separation and transfer,as well as surface activity of photoanode.In principle,water oxidation is initiated by the photo-excited charge of photoanode.In this review,we took hematite photoanode as a typical example to illustrate the progress in modifying the charge separation and migration property of metal-oxide photoanodes for water oxidation.The typical strategies adopted to facilitate the charge transfer and separation of hematite photoanode were specifically summarized.In addition,the views designing and developing hematite photoanode with high-performance for water oxidation were presented.This review provides comprehensive information about the state-of-the-art progress of hematite-based photoanodes and forecast the developing directions of photoanode materials for solar water splitting.

天鲲号绞吸挖泥船挖岩作业配套船舶技术研究

随着全球经济增长和疏浚业的扩大,大型绞吸挖泥船已成为这一领域的关键装备。文章专注于提升超大型绞吸挖泥船“天鲲号”的效能。通过分析该船在挖岩工程中的挑战,引入了“挖-运分离”的高效物流策略。为实现这一目标,建议开发一艘专门与天鲲号配套使用的开体式耙吸挖泥船。文章详细讨论了开体式耙吸挖泥船在主尺度和舱容、快速靠泊、泥舱结构和强度、疏浚系统和船舶布局等方面与天鲲号的匹配问题。提出了一个新颖的开体式耙吸挖泥船方案,能够完全满足配合天鲲号挖岩装驳和运输的需求,实现“挖-运分离”物流策略;能够开展后期扫浅挖泥作业,减少天鲲号的占用期,从而显著提升整体经济效益。

考虑碳排放带时间窗的商超配送路径优化

针对商超配送多批次、小批量的实际情况,综合考虑了需求点的服务时间窗、最小配送量、访问次数等要求,设计了一种新的拆分策略,即“最大车辆载重量—最小配送量”需求拆分策略,构建相关商超配送车辆路径优化模型,并使用人工免疫算法对该模型进行求解。由于需求拆分车辆路径问题是一个复杂的组合优化过程,考虑到传统人工免疫算法局部搜索能力不足的局限,设计了多种变邻域操作改进人工免疫算法,并采用轮盘赌选择法将变邻域操作用于抗体突变,形成变邻域人工免疫算法。通过数值仿真实验,结果显示,变邻域人工免疫算法比人工免疫算法求得的综合成本平均优化3%~5%,碳排放相关成本平均降低5%~10%。

CR-RSMA网络接入控制策略研究

针对多个次用户的速率分割多址接入技术辅助的认知无线电(CR-RSMA,cognitive radio-inspired rate splittingmultipleaccess)网络设计了一种接入控制策略,在主用户实现与正交多址接入(OMA,orthogonal multiple access)相同的中断性能并满足次用户通信服务质量(QoS,quality of service)需求的前提下,让更多的次用户接入主用户频段,并在此基础上最大化次用户吞吐量之和。该策略考虑次用户QoS约束,联合优化次用户发射功率分配因子和接入次用户集合,推导出最优功率分配因子的闭合表达式,进而求得次用户最大通信速率和最小通信时间,在此基础上利用贪婪搜索算法确定最终接入的次用户,最后通过优化时间资源实现所有接入次用户吞吐量之和的最大化。仿真结果表明,该策略相比于非正交多址接入技术辅助的认知无线电(CR-NOMA,cognitive radio-inspired non-orthogonal multiple access)网络在接入用户数和吞吐量方面均表现出更优越的性能。

Out-of-step oscillation splitting criterion based on bus voltage frequency

Under the background of complicated interconnected network,the splitting criterion for accurately capturing the electrical center in real time is the prerequisite of power grid splitting.This paper studies the features of electric quantity in the electrical center in aspect of the instantaneous frequency,and proposes the out-of-step splitting criterion for power systems based on bus voltage frequency.Firstly,through the establishment and solution to the out-of-step model of the power grid,the analytical expression of the voltage frequency at any position is obtained in the out-of-step oscillation,and the voltage frequency features of electrical center and non-electrical center are analyzed in details.Then,this paper constructs the typical scene of migration of electrical center to study the change rules of voltage frequency.Finally,the splitting criterion based on bus voltage frequency is proposed as well as the instruction for use.This criterion is easy to be realized and can adapt to the migration of electrical center.Also it is free from the limits of power network structure and operational mode.Simulation results of CEPRI-36 system and interconnected network example of one actual region verify the accuracy and the effectiveness of the proposed criterion.

尖孢镰刀菌亚麻专化型FolSwe1基因功能分析

本文旨在对尖孢镰刀菌亚麻专化型FolSwe1基因进行功能分析。利用同源比对,通过PCR对FolSwe1基因及其侧翼序列进行扩增和测序,使用Split-Marker技术构建该基因缺失突变盒,使用聚乙二醇(PEG)介导转化野生型原生质体,获得了FolSwe1基因缺失突变株,对突变体表型和致病力进行测定。构建荧光载体pZESH1(pZWH1+EGFP+FolSwe1)对FolSwe1蛋白进行亚细胞定位。结果显示,FolSwe1基因编码区为3219 bp,含有一个内含子,长度为54 bp,所测序列包括编码区上游1704 bp,编码区下游为1694 bp。表型观察发现,敲除突变体的菌丝比野生型短小且密实,菌落生长速度较慢,特别显著的变化是缺失突变体不再产生孢子,致病力也明显下降。亚细胞定位显示FolSwe1蛋白在培养时间较长菌丝的细胞膜中有荧光信号。综上所述,FolSwe1基因主要调控尖孢镰刀菌亚麻专化型的孢子发生、菌丝营养生长和对亚麻的致病性。

Active splitting strategy searching approach based on MISOCP with consideration of power island stability

Active splitting control utilizes real-time decision and system-level splitting to prevent cascading blackouts and to maintain power supply under severe disturbances. Splitting strategy searching(SSS) is one of the most crucial issues in active splitting control for deciding‘‘where to split’’. SSS determines the splitting surface in real time to properly divide the asynchronous generators into isolated islands with an optimal control effect. In this paper, an SSS approach that focuses on island stability is presented. The proposed SSS approach is designed to ensure a rational stability margin and regulation ability on each island during and after the transient process of system splitting. This method includes the active/reactive power flow feasibility constraints and voltage/angle stability constraints in the steady state as well as the frequencyresponse capability constraints in the transient process. By considering the island stability constraints in the SSS, the proposed approach can avoid the splitting strategies with poor stability performance. Therefore, the major advantage of the proposed approach is that it can ensure better island static and transient stability during and after the splitting control. In addition, the entire model is formulated as a mixed-integer second-order cone programming(MISOCP)model. Thus, it can be rapidly solved by using commercial optimization solvers. Numerical simulations of a realistic provincial power system in central China demonstrate thevalidity of the proposed approach and the necessity of considering the island stability issues.

Enhancing electrical conductivity of single-atom doped Co_(3)O_(4) nanosheet arrays at grain boundary by phosphor doping strategy for efficient water splitting

High electrical conductivity guarantees a rapid electron transfer and thus plays an important role in electrocatalysis.In particular,for the single atom catalysts(SACs),to facilitate interaction between the single atom and supports,precisely engineering the conductivity represents a promising strategy to design SACs with high electrochemical efficiency.Here we show rhodium(Rh)SAC anchored on Co_(3)O_(4) nanosheets arrays on nickel foam(NF),which is modified by a facile phosphorus(P-doped Rh SACCo_(3)O_(4)/NF),possessing an appropriate electronic structure and high conductivity for electrocatalytic reaction.With the introduction of P atom in the lattice,the electrocatalyst demonstrates outstanding alkaline oxygen evolution reaction(OER)activity with 50 mA·cm^(−2) under overpotential of 268 mV,6 times higher than that of Ir/C/NF.More interestingly,the P-doped Rh SAC-Co_(3)O_(4)/NF can get 50 mA·cm^(−2) at only 1.77 V for overall water splitting.Both electrical conductivity studies and density functional theory(DFT)calculations reveal that the high conductivity at grain boundary improves the charge transfer efficiency of the Rh catalytic center.Furthermore,other noble-metal(Ir,Pd,and Ru)doped Co_(3)O_(4) nanosheets arrays are prepared to exhibit the general efficacy of the phosphorus doping strategy.

Innovative Strategies for Overall Water Splitting Using Nanostructured Transition Metal Electrocatalysts

Electrochemical water splitting is regarded as the most auspicious technology for renewable sources,transport,and storage of hydrogen energy.Currently,noble Pt metal and noble-metal oxides(IrO_(2)and RuO_(2))are recognized as state-of-the-art electrocatalysts for both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),respectively.Searching for earth-abundant electrocatalysts for the HER and OER with remarkable performance and high stability to replace precious metals plays a significant role in the commercial application of electrochemical water splitting.In this review,recent advancements in nanostructured transition metal electrocatalysts are assessed through the selected examples of nitrides,carbides,phosphides,sulfides,borides,layered double hydroxides,and oxides.Recent breakthroughs in nanostructured transition metal electrocatalysts are discussed in terms of their mechanisms,controllable production,structural design,and innovative strategies for boosting their performance.For instance,most nanostructured transition metal electrocatalysts for overall water splitting(OWS)only function well in neutral and alkaline solutions.Finally,current research challenges and future perspectives for increasing the performance of nanostructured transition metals for OWS are proposed.

考虑新能源并网影响的零序过电压解列策略

目前新能源并网故障零序过压解列判据按躲过中性点直接接地系统正常运行时的不平衡电压整定,解列时间与新能源场站的变压器间隙零序过压保护配合。然而当线路发生高阻接地短路或者线路的保护Ⅱ段范围内发生故障时,该策略存在新能源大面积误解列问题。为此文章提出一种可靠防止新能源大面积误解列的零序过压解列策略的改进方法,并设计了解列判据,通过仿真以及实际故障验证了策略的有效性。结果表明,该解列策略具有高可靠性和实用性。

Si光阳极稳定性提高策略研究进展

利用光电化学水分解技术实现绿氢制取是解决人类面临的能源危机和环境污染的极有效与可行的途径之一,受到广泛的关注与研究。半导体Si作为一种优异的光电极材料,具有理想的1.12 eV窄带隙、宽太阳光谱吸收范围(300~1100 nm)、高的载流子传输性能(晶体硅μn=1350 cm^(2)/(V·s),μp=500 cm^(2)/(V·s),常温)以及高结晶性等优点。但是,Si的价带边远低于水分解析氧反应1.23 VRHE,以及析氧反应涉及四电子转移过程,导致Si光阳极本征析氧反应动力学缓慢;同时,Si光阳极表面会生成绝缘性SiO_(2)层或SiO_(2)(OH)^(2-)层,导致严重的光腐蚀和稳定性问题等,成为限制其实际应用的重大挑战。近年来,研究者提出了许多提高Si光阳极光氢转换效率与稳定性的策略。本文重点对Si光阳极的提高策略研究进展进行综述,包括催化层、保护层、电解液保护以及界面工程四类;其次对光电化学水分解基本原理以及Si半导体材料作光阳极的可行性与优缺点进行分析;最后基于上述研究进展,对提高Si光阳极效率与稳定性的未来发展进行了综述与展望。

Designing Electrocatalysts for High-Current-Density Freshwater/Seawater Splitting

Electrocatalytic water splitting is crucial to renewable and clean hydrogen generation.Achieving high efficiency and stability in hydrogen generation by freshwater/seawater electrolysis at a high current density(HCD)using low-cost electrode materials is of utmost importance for the future hydrogen economy.However,conventional freshwater/seawater electrolysis suffers from low current density due to inefficient electrocatalysts and competitive reactions of the chlorine evolution reaction(ClER),consequently hampering its industrial adoption.Advanced surface and interface engineering techniques are essential for the development of efficient and long-lasting electrodes for freshwater and seawater electrolysis at HCD.In the review,we begin by discussing the fundamental aspects of freshwater/seawater splitting,focusing on recent advancements and strategies to increase the efficiency at HCD.We then comprehensively discuss the rational design strategies for the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)at HCD together with the associated fundamental electrode reactions by considering the thermodynamic and kinetic aspects of the catalytic efficiency,selectivity,and corrosion resistance.It is followed by a discussion of some existing issues and limitations of HCD freshwater/seawater splitting and viable solutions.Finally,the issues facing the field and possible future research directions for efficient large-scale industrial water splitting are discussed.

振荡中心迁移下的电网失步解列策略

振荡中心迁移严重危害电网的安全稳定,选取合适的解列判据,准确定位并实施解列具有重要意义。基于等值两机系统推导分析振荡中心迁移的理论原因,分析失步过程中电压的变化特点,依据两侧系统频率差与失步中心出现频率的对应关系提出基于支路两端母线频率差的失步解列判据;针对振荡中心迁移对失步解列控制的影响,提出了基于广域测量信息的自适应失步解列策略。通过对某区域互联电网进行仿真分析,发现振荡中心迁移现象,认为失稳模式的改变是振荡中心迁移的直接原因,并进行解列策略的仿真验证。仿真结果证明了所提出的解列策略的有效性。