Oxygen Evolution Reaction in Energy Conversion and Storage: Design Strategies Under and Beyond the Energy Scaling Relationship

The oxygen evolution reaction(OER)is the essential module in energy conversion and storage devices such as electrolyzer,rechargeable metal–air batteries and regenerative fuel cells.The adsorption energy scaling relations between the reaction intermediates,however,impose a large intrinsic overpotential and sluggish reaction kinetics on OER catalysts.Developing advanced electrocatalysts with high activity and stability based on non-noble metal materials is still a grand challenge.Central to the rational design of novel and high-efficiency catalysts is the development and understanding of quantitative structure–activity relationships,which correlate the catalytic activities with structural and electronic descriptors.This paper comprehensively reviews the benchmark descriptors for OER electrolysis,aiming to give an in-depth understanding on the origins of the electrocatalytic activity of the OER and further contribute to building the theory of electrocatalysis.Meanwhile,the cutting-edge research frontiers for proposing new OER paradigms and crucial strategies to circumvent the scaling relationship are also summarized.Challenges,opportunities and perspectives are discussed,intending to shed some light on the rational design concepts and advance the development of more efficient catalysts for enhancing OER performance.

Exploring landslide erosion volume-area scaling relationships by slip depth using changes in DTMs for basin sediment volume estimation

Landslides produce large quantities of sediment deposits and reduce reservoir life. This study investigated landslides at the Shihmen Reservoir basin in Taiwan that were induced by Typhoon Sinlaku and Typhoon Jangmi in 2008. We formulate scaling relationships between landslide erosion volume and area and conclude that sediment budget can be estimated based on the easier-todetermine landslide erosion area. The methodologies applied for the investigation were geomorphological analysis through 5 m × 5 m digital terrain models(DTMs) of the basin created before and after the landslide events and spatial analysis through a geographic information system. The erosion area and volume of landslides were measured through the subtraction of DTMs produced before and after the events. Statistical analysis revealed that the landslide erosion frequency–magnitude distribution exhibited power-law behaviors with a scaling exponent of 2.15 for the frequency–area distribution and 1.66 for the frequency–volume distribution. This paper proposes different scaling relationships for different moving depths, and landslide erosion volumes were estimated on the basis of depth; thus, landslides of different scales can be distinguished to avoid errors in volume estimation. Two different scaling exponents are proposed: 1.21 for landslide erosions with depths of less than 2 m and 1.01 for landslide erosions with depths of more than 2 m. The proposed scaling relationships are practical for landslide erosion volume estimation by different depths according to the landslide area, and they can provide preliminary results for sediment budget planning in a reservoir basin.

The scaling relationship of leaf area and total mass of sample plots across world trees

The scaling relationship between leaf area and total mass of plant has important implications for understanding resource allocations in the plant.The model of West,Brown and Enquist(WBE model)considers that a 3/4 scaling exponent of metabolic rate versus total mass to be optimal for each plant and has been confirmed numerous times.Although leaf area is a better proxy of the metabolic rate than leaf mass,few studies have focused on the scaling exponent of leaf area versus total mass and even fewer have discussed the diversification of this scaling exponent across different conditions.Here,I analyzed the scaling exponent of leaf area versus total mass of sample plots across world plants.I found that as the plant grows,it allocates fewer resources to photosynthetic tissues than expected by the WBE model.The results also empirically show that this scaling exponent varies significantly for different plant leaf habit,taxonomic class and geographic region.Therefore,leaf strategy in response to environmental pressure and constraint clearly plays a significant role.

Using Quantile Regression to Detect Relationships between Large-scale Predictors and Local Precipitation over Northern China

Quantile regression（QR） is proposed to examine the relationships between large-scale atmospheric variables and all parts of the distribution of daily precipitation amount at Beijing Station from 1960 to 2008. QR is also applied to evaluate the relationship between large-scale predictors and extreme precipitation（90th quantile） at 238 stations in northern China.Finally, QR is used to fit observed daily precipitation amounts for wet days at four sample stations. Results show that meridional wind and specific humidity at both 850 h Pa and 500 h Pa（V850, SH850, V500, and SH500） strongly affect all parts of the Beijing precipitation distribution during the wet season（April–September）. Meridional wind, zonal wind, and specific humidity at only 850 h Pa（V850, U850, SH850） are significantly related to the precipitation distribution in the dry season（October–March）. Impacts of these large-scale predictors on the daily precipitation amount with higher quantile become stronger, whereas their impact on light precipitation is negligible. In addition, SH850 has a strong relationship with wet-season extreme precipitation across the entire region, whereas the impacts of V850, V500, and SH500 are mainly in semi-arid and semi-humid areas. For the dry season, both SH850 and V850 are the major predictors of extreme precipitation in the entire region. Moreover, QR can satisfactorily simulate the daily precipitation amount at each station and for each season, if an optimum distribution family is selected. Therefore, QR is valuable for detecting the relationship between the large-scale predictors and the daily precipitation amount.

Scaling Relationships for Input Energy in Electromagnetic Welding of Similar and Dissimilar Metals

In Electromagnetic Welding (EMW) process, the capacitive energy is the source of input energy. The tool that is used for welding comprises of an electromagnetic coil. The job piece to be welded is placed in close proximity with the coil. The welding is achieved by impact, when the colliding job pieces are accelerated towards each other by the Lorentz force. The electromagnetic and mechanical properties/ parameters of the equipment, tool and the job govern the overall welding process. We have described a procedure to calculate the capacitive input energies for jobs of different sizes. Data is given for welding of strips of aluminium, copper and S.S. in similar and dissimilar combinations. Since the EMW technique is used in limited applications, this type of data is not available. We have validated our model with some data available in the literature. It is hoped that, this information will help the designer, to select and standardize the system and process parameters.

Generating highly active oxide-phosphide heterostructure through interfacial engineering to break the energy scaling relation toward urea-assisted natural seawater electrolysis

Urea-assisted natural seawater electrolysis is an emerging technology that is effective for grid-scale carbon-neutral hydrogen mass production yet challenging.Circumventing scaling relations is an effective strategy to break through the bottleneck of natural seawater splitting.Herein,by DFT calculation,we demonstrated that the interface boundaries between Ni_(2)P and MoO_(2) play an essential role in the selfrelaxation of the Ni-O interfacial bond,effectively modulating a coordination number of intermediates to control independently their adsorption-free energy,thus circumventing the adsorption-energy scaling relation.Following this conceptual model,a well-defined 3D F-doped Ni_(2)P-MoO_(2) heterostructure microrod array was rationally designed via an interfacial engineering strategy toward urea-assisted natural seawater electrolysis.As a result,the F-Ni_(2)P-MoO_(2) exhibits eminently active and durable bifunctional catalysts for both HER and OER in acid,alkaline,and alkaline sea water-based electrolytes.By in-situ analysis,we found that a thin amorphous layer of NiOOH,which is evolved from the Ni_(2)P during anodic reaction,is real catalytic active sites for the OER and UOR processes.Remarkable,such electrode-assembled urea-assisted natural seawater electrolyzer requires low voltages of 1.29 and 1.75 V to drive 10 and600 mA cm^(-2)and demonstrates superior durability by operating continuously for 100 h at 100 mA cm^(-2),beyond commercial Pt/C||RuO_(2) and most previous reports.

Multi-scale spatial relationships between soil total nitrogen and influencing factors in a basin landscape based on multivariate empirical mode decomposition

The relationships between soil total nitrogen(STN)and influencing factors are scale-dependent.The objective of this study was to identify the multi-scale spatial relationships of STN with selected environmental factors(elevation,slope and topographic wetness index),intrinsic soil factors(soil bulk density,sand content,silt content,and clay content)and combined environmental factors(including the first two principal components(PC1 and PC2)of the Vis-NIR soil spectra)along three sampling transects located at the upstream,midstream and downstream of Taiyuan Basin on the Chinese Loess Plateau.We separated the multivariate data series of STN and influencing factors at each transect into six intrinsic mode functions(IMFs)and one residue by multivariate empirical mode decomposition(MEMD).Meanwhile,we obtained the predicted equations of STN based on MEMD by stepwise multiple linear regression(SMLR).The results indicated that the dominant scales of explained variance in STN were at scale 995 m for transect 1,at scales 956 and 8852 m for transect 2,and at scales 972,5716 and 12,317 m for transect 3.Multi-scale correlation coefficients between STN and influencing factors were less significant in transect 3 than in transects 1 and 2.The goodness of fit root mean square error(RMSE),normalized root mean square error(NRMSE),and coefficient of determination(R2)indicated that the prediction of STN at the sampling scale by summing all of the predicted IMFs and residue was more accurate than that by SMLR directly.Therefore,the multi-scale method of MEMD has a good potential in characterizing the multi-scale spatial relationships between STN and influencing factors at the basin landscape scale.

The relationship between farm size and fertilizer use efficiency:Evidence from China

Low fertilizer use efficiency is commonly found in China’s agriculture sector. It is critical to understand the drivers of fertilizer use in order to increase fertilizer use efficiency(FUE). The purpose of this paper is to investigate the relationship between farm size and FUE based on farm-level data in China. The results suggest a positive farm size–FUE relationship. The estimated elasticities of farm size for rice, maize, wheat–maize, and rice–maize are similar, and the average elasticity of farm size is around 0.2. Statistically, a 1% increase in farm size is associated with a 0.2%increase in FUE. The positive effect of farm size on FUE is not due to the increase in yield, but the reduction in fertilizer use while keeping yield largely unchanged. The findings suggest that promoting the expansion of farm size may increase FUE, and thus reduce environmental pollution caused by fertilizer overuse.

Impacts of Multi-Scale Solar Activity on Climate.Part Ⅱ:Dominant Timescales in Decadal-Centennial Climate Variability

Part II of this study detects the dominant decadal-centennial timescales in four SST indices up to the 2010/2011 winter and tries to relate them to the observed 11-yr and 88-yr solar activity with the sunspot number up to Solar Cycle 24. To explore plausible solar origins of the observed decadal-centennial timescales in the SSTs and climate variability in general, we design a simple one-dimensional dynamical system forced by an annual cycle modulated by a small-amplitude single- or multi-scale ＂solar activity.＂ Results suggest that nonlinear harmonic and subharmonic resonance of the system to the forcing and period-doubling bifurcations are responsible for the dominant timescales in the system, including the 60-yr timescale that dominates the Atlantic Multidecadal Oscillation. The dominant timescales in the forced system depend on the system＇s parameter setting. Scale enhancement among the dominant response timescales may result in dramatic amplifications over a few decades and extreme values of the time series on various timescales. Three possible energy sources for such amplifications and extremes are proposed. Dynamical model results suggest that solar activity may play an important yet not well recognized role in the observed decadal-centennial climate variability. The atmospheric dynamical amplifying mechanism shown in Part I and the nonlinear resonant and bifurcation mechanisms shown in Part II help us to understand the solar source of the multi-scale climate change in the 20th century and the fact that different solar influenced dominant timescales for recurrent climate extremes for a given region or a parameter setting. Part II also indicates that solar influences on climate cannot be linearly compared with non-cyclic or sporadic thermal forcings because they cannot exert their influences on climate in the same way as the sun does.

Parameterizations of the Daytime Friction Velocity, Temperature Scale, and Upslope Flow over Gently Inclined Terrain in Calm Synoptic Conditions

A set of new parameterizations for the friction velocity and temperature scale over gently sloped terrain and in calm synoptic conditions are theoretically derived. The friction velocity is found to be proportional to the product of the square root of the total accumulated heating in the boundary layer and the sinusoidal function of the slope angle, while the temperature scale is proportional to the product of the boundary layer depth, the sinusoidal function of the slope angle and the potential temperature gradient in the free atmosphere. Using the new friction velocity parameterization, together with a parameterization of eddy diffusivity and an initial potential temperature profile around sunrise, an improved parameterization for the thermally induced upslope flow profile is derived by solving the Prandtl equations. The upslope flow profile is found to be simply proportional to the friction velocity.

A combinatorial descriptor for volcano relationships of electrochemical nitrogen reduction reaction

Though touted as a potential way to realize clean ammonia synthesis,electrochemical ammonia synthesis is currently limited by its catalytic efficiency.Great effort has been made to find catalysts with improved activity toward electrochemical nitrogen reduction reaction(eNRR).Rational screening of catalysts can be facilitated using the volcano relationship between catalytic activity and adsorption energy of an intermediate,namely,the activity descriptor.In this work,we proposeΔG^(*)_(NH_(2))+ΔG^(*)_(NNH)as a combinatorial descriptor,which shows better predictive power than traditional descriptors using the adsorption free energies of single intermediates.The volcano plots based on the combinatorial descriptor exhibits peak activity fixedly at the descriptor value corresponding to the formation free energy of NH3,regardless of the catalyst types;while the descriptor values correspond to the top activities for eNRR on volcano plots based on single descriptors usually vary with the types of catalysts.

Violating of the Essam-Fisher and Rushbrooke Relationships at Low Temperatures

The Essam-Fisher and Rushbrooke relationships (1963) that connect the equilibrium critical exponents of susceptibility, specific heat and order parameter (and some other relations that follow from the scaling hypothesis) are shown to be valid only if the critical temperature TС > 0 and T → TC. For phase transitions (PT’s) with TC = 0 K these relations are proved to be of different form. This fact has been actually observed experimentally, but the reasons were not quite clear. A general formula containing the classical results as a special case is proposed. This formula is applicable to all equilibrium PT’s of any space dimension for both TC = 0 and TC > 0. The predictions of the theory are consistent with the available experimental data and do not cast any doubts upon the scaling hypothesis.

壳源氦气成藏主控因素及资源评价方法研究

当前国内外尚无系统的氦气资源评价方法以及针对性的参数取值标准。通过天然气和氦气的成藏要素对比,明确了载体气和壳源氦气的异源同储、同源同储和同源异储3类共生关系,以及壳源氦气成藏的8个关键因素。构建了4类10种氦气资源分级分类评价方法,其中含量法包括5个亚类,统计法包括1个亚类,类比法包括3个亚类,成因法1个亚类,初步解决了氦气资源定量计算的难题。结果表明:高氦气含量的气藏一般为常压及低压气藏,氦气含量与氦源岩类型、铀钍含量和氦源岩规模3个参数呈正向关系,而与离主断裂距离、埋深和生烃强度3个参数呈负相关,适度的基底构造活动有利于氦气释放及富集。基于8类氦气成藏主控因素与氦气含量的定量关系,建立了氦气含量类比法。基于异源同储不同序的原理,构建了氦气资源规模序列法;基于放射性元素衰变释氦机理,建立了氦气成因法。氦气资源评价方法在国内外得到了较为广泛的应用,研究成果将为我国氦气储量规模发现提供了有效支撑。

基于深度学习的塑性变形理论建模研究进展

传统塑性理论模型由于引入了适当的假设和简化,面对复杂变形机制和复杂变形条件时具有局限性。基于深度学习的理论建模作为数据驱动的建模新范式,具有精度高、通用性强的特点,是塑性理论建模的重要方向。介绍了深度学习的建模方法,如传统神经网络模型、物理启发式神经网络模型和神经算子网络,分析了各个模型的特点。总结了近年来基于深度学习的塑性理论建模方法在本构关系、损伤断裂模型、微观组织模型和多尺度模型等方面应用的研究进展,并分析了提高模型精度、泛化能力和可解释性的方法。最后提出了基于深度学习的塑性理论建模方法面临的挑战和未来发展方向。

闽江流域多时间尺度降雨—径流关系变化与成因

为进一步揭示闽江流域降雨—径流关系的时空变化规律,识别主要驱动因子,基于1960—2019年降雨和径流数据,应用TFPW—MK方法,按照年以及年内的汛期与非汛期、前汛期和后汛期、最大月和最小月等不同时间尺度,检测闽江上游三大支流、干流及全流域等空间尺度的降雨—径流演变趋势;结合Sen trend方法,从气候变化、土地利用和水库工程建设3方面,分析影响降雨—径流关系变化的成因。结果表明:1)闽江流域及各支流年降雨—径流均呈不显著上升,趋势变化一致;2)除支流建溪流域,闽江及其他支流非汛期降雨—径流上升趋势显著;汛期内部趋势变化分化明显,前汛期降雨—径流略减少,后汛期降雨—径流大部分显著增加;3)极端降雨—径流的变化趋势不一致,主要受大型水库工程建设的影响。基于多时间尺度的分析,更深入揭示闽江流域降水、径流的演变及气候变化与人类活动的影响,对区域水资源管理与水土保持具有重要参考价值。

岩石多尺度损伤研究进展

岩石损伤破裂是一个从微观到细观到宏观的多尺度链动损伤破裂过程。明确岩石不同尺度损伤特征并建立多尺度损伤的定量化关系对复杂环境下岩石多尺度损伤劣化机理研究至关重要。近年来,研究人员针对复杂环境下岩石多尺度损伤机理开展大量的研究工作,并取得了一定的研究成果。本文从岩石多尺度损伤特征、不同尺度损伤识别与定量化表征、多尺度损伤量效关系3个方面系统评述了岩石多尺度损伤研究进展。首先,总结了岩石微观、细观、宏观损伤特征,分析了岩石多尺度累积损伤破裂过程;其次,基于岩石多尺度损伤特征,系统评述岩石微观、细观和宏观损伤的识别方法以及不同尺度损伤的定量化表征方法,分析了岩石微观-细观-宏观损伤量效关系确定方法;最后,从多尺度损伤识别、定量化表征、量效关系确定方面分析了岩石多尺度损伤研究中存在的不足,提出了从:开发适用于多场耦合环境的岩石微细观损伤实时识别设备,建立岩石三维空间多尺度损伤协同智能化定量表征方法,构建完善的岩石微-细-宏观多尺度损伤量效关系研究体系,丰富创新岩石多尺度损伤理论几方面开展岩石多尺度损伤研究。

基于长短期时间关系网络的视频行人重识别

行人重识别是计算机视觉领域中的一个重要研究方向,其目的是在不同的监控摄像头中识别并跟踪同一行人.由于视频帧间存在多种时间关系,从这些关系中可以获取到对象的运动模式以及细粒度特征,因此视频重识别相比图像重识别拥有更丰富的时空线索,也更接近实际应用.问题的关键是如何挖掘这些时空线索作为视频重识别的特征.本文针对视频行人重识别问题,提出了一种基于Transformer的长短期时间关系网络(Long and Short Time Transformer,LSTT).该网络包含长短期时间关系模块,提取重要时序信息并强化特征表示.长期时间关系模块利用记忆线索存储每帧信息,并在每一帧建立全局联系;短期时间关系模块则考虑相邻帧之间交互,学习细粒度目标信息,提高特征表示能力.此外,为了提高模型对不同目标特征的适配性,本文还设计了一个包含不同规格卷积核的多尺度模块.该模块具有多种卷积感受野,能够更全面覆盖目标区域,从而进一步提高模型的泛化性能.在MARS、MARS_DL和iLIDS-VID 3个数据集上的实验结果表明,LSTT模型性能最优.

凉水保护区红松与主要伴生树种的空间关系

空间关系是影响森林生长与群落演替的重要因素,种间关系是其重要组成部分,研究空间关系有利于了解森林群落的生长更新、功能作用与演替进程。利用移动窗口法对凉水自然保护区10.4 hm^(2)样地不同径级的红松与主要伴生树种做空间相关性研究,并进行多尺度比较,得到不同尺度下不同径级红松与主要伴生树种个体的空间关系特征。研究结果表明:(1)红松与伴生树种的相互关系复杂多样,多种相互关系并存,表现出阔叶红松林群落结构的复杂性与稳定性。大径级红松压制同径级伴生树种,二者呈极显著负相关,但其对小径级伴生树种有庇荫作用,二者呈极显著正相关。(2)红松与主要伴生树种的相互关系在不同尺度、径级上均有极显著差异。尺度越大,红松与主要伴生树种的相关系数变化速率越小;伴生树种的径级越大,红松与主要伴生树种的相关系数变化速率越大。(3)红松与伴生树种的相关性具有尺度特征,主要表现在大尺度(≥60 m)范围上,在小尺度(<60 m)上相关性较弱。红松与伴生树种在相同径级与不同径级的结合方式上表现出不同的空间关系。同径级的红松与伴生树的种间关系多表现为负相关,不同径级的红松与伴生树种种间关系多表现为正相关。(4)以种间关系确定样方最小面积,凉水保护区临界样地面积为60 m×60 m。该研究集中于不同尺度下不同径级的红松与伴生树种的种间关系,解释优势种红松与伴生树种在森林的空间关系以及群落结构特征,为东北地区阔叶红松林的森林管理提供参考意见。

粤港澳大湾区生态系统服务供需关系及其对城市化多空间尺度的响应

城市化与生态系统服务供需相互作用关系在不同空间尺度下具有显著差异性。基于供需空间不匹配视角揭示生态系统服务对城市化的多尺度响应规律是实现城市可持续性发展的重要前提条件。研究从1 km×1 km、2.5 km×2.5 km、5 km×5 km、10 km×10 km、区县域和市域等6个空间尺度分析了2020年粤港澳大湾区生境质量服务、固碳服务和土壤保持服务供需关系和空间分异规律,并探究不同空间尺度生态系统服务供需关系对城市化的响应。结果表明:(1)生态系统供需错配集中分布在中心城区,空间尺度的增加加剧了中心城区的赤字程度。(2)城市化指数与生态系统服务供需比率在多空间尺度上均呈负相关关系。随着空间尺度增加,高城市化-生态系统服务赤字型逐渐向中心城区延伸,低城市化-生态系统服务盈余型向非城市化地区聚集。(3)在10 km和区县尺度上,生态系统服务供需对城市化响应最为剧烈,是解决二者不平衡发展的最佳尺度。本研究为高度城市化地区相关管理部门提供优化生态系统服务供需平衡的保护管理政策制定提供科学依据。

基于矿业权数据的空间关系压覆智能比对关键技术研究及实现

为解决传统矿业权空间关系压覆查询比对效率低下、易产生遗漏错误、审批时效长等问题,进一步提升政务服务审批效率,本文探索基于自然资源数据“一张图”,利用高性能IGServer等信息技术,建设矿业权数据空间压覆智能比对“数字员工”系统,研究智能比对分析和动态调整比例尺、动态注记等关键技术,输出图文分析报告。研究结果表明,相比于传统的人工比对分析方式,由大数据支持的“数字员工”自动化空间压覆智能比对方法,有效提高了分析效率和结果的精准度,快速精准支撑政务服务审批,合理保护矿产资源和保障建设项目顺利实施。