Wind power operation capacity credit assessment considering energy storage

Research on wind power capacity credit at the operational level plays an important role in power system dispatching.With the popularity of energy storage devices,it is increasingly necessary to study the impact of energy storage devices on wind power operational capacity credit.The definition of wind power operational capacity credit is given.The available capacity model of different generators and the charging and discharging model of the energy storage are established.Based on the above model,the evaluation method of wind power operation credible capacity considering energy storage devices is proposed.The influence of energy storage on the wind power operation credible capacity is obtained by case study,which is of great help for the power system dispatching operation and wind power accommodation.

Extreme scenario extraction of a grid with large scale wind power integration by combined entropy-weighted clustering method

Large-scale integration of wind power into a power system introduces uncertainties to its operation and planning,making the power system operation scenario highly diversified and variable.In conventional power system planning,some key operation modes and most critical scenarios are typically analyzed to identify the weak and high-risk points in grid operation.While these scenarios may not follow traditional empirical patterns due to the introduction of large-scale wind power.In this paper,we propose a weighted clustering method to quickly identify a system’s extreme operation scenarios by considering the temporal variations and correlations between wind power and load to evaluate the stability and security for system planning.Specifically,based on an annual time-series data of wind power and load,a combined weighted clustering method is used to pick the typical scenarios of power grid operation,and the edge operation points far from the clustering center are extracted as the extreme scenarios.The contribution of fluctuations and capacities of different wind farms and loads to extreme scenarios are considered in the clustering process,to further improve the efficiency and rationality of the extreme-scenario extraction.A set of case studies was used to verify the performance of the method,providing an intuitive understanding of the extreme scenario variety under wind power integration.

High-entropy alloy catalysts:From bulk to nano toward highly efficient carbon and nitrogen catalysis

High-entropy alloys(HEAs)have attracted widespread attention as both structural and functional materials owing to their huge multielement composition space and unique high-entropy mixing structure.Recently,emerging HEAs,either in nano or highly porous bulk forms,are developed and utilized for various catalytic and clean energy applications with superior activity and remarkable durability.Being catalysts,HEAs possess some unique advantages,including(1)a multielement composition space for the discovery of new catalysts and fine-tuning of surface adsorption(i.e.,activity and selectivity),(2)diverse active sites derived from the random multielement mixing that are especially suitable for multistep catalysis,and(3)a high-entropy stabilized structure that improves the structural durability in harsh catalytic environments.Benefited from these inherent advantages,HEA catalysts have demonstrated superior catalytic performances and are promising for complex carbon(C)and nitrogen(N)cycle reactions featuring multistep reaction pathways and many different intermediates.However,the design,synthesis,characterization,and understanding of HEA catalysts for C-and N-involved reactions are extremely challenging because of both complex high-entropy materials and complex reactions.In this review,we present the recent development of HEA catalysts,particularly on their innovative and extensive syntheses,advanced(in situ)characterizations,and applications in complex C and N looping reactions,aiming to provide a focused view on how to utilize intrinsically complex catalysts for these important and complex reactions.In the end,remaining challenges and future directions are proposed to guide the development and application of HEA catalysts for highly efficient energy storage and chemical conversion toward carbon neutrality.

Non-noble-metal electrocatalysts for oxygen evolution reaction toward seawater splitting: A review

The direct electrolytic splitting of abundant seawater instead of scarce freshwater is an ideal strategy for producing clean and renewable hydrogen(H 2)fuels.The oxygen evolution reaction(OER)is a vital half-reaction that occurs during electrochemical seawater splitting.However,OER suffers from sluggish four-electron transfer kinetics and competitive chlorine evolution reactions in seawater.Noble metal-based catalysts such as IrO_(2) and RuO_(2) are considered to have state-of-the-art OER electrocatalytic activity,but the low reserves and high prices of these noble metals significantly limit their large-scale application.Recently,efforts have been made to explore efficient,robust,and anti-chlorine-corrosion non-noble-metal OER electrocatalysts for seawater splitting such as oxides,hydroxides,phosphides,nitrides,chalcogenides,alloys,and composites.An in-depth understanding of the fundamentals of seawater electrolysis and the design principle of electrode materials is important for promoting seawater-splitting technology.In this review,we first introduce fundamental reactions in seawater electrolytes.Subsequently,construction strategies for OER electrocatalysts for seawater splitting are introduced.Finally,present challenges and perspectives regarding non-noble-metal OER electrocatalysts for commercial H 2 production by seawater splitting are discussed.

Design strategies and recent advancements of solid-state supercapacitor operating in wide temperature range

Solid-state supercapacitors(SSCs)are emerging as one of the promising energy storage devices due to their high safety,superior power density,and excellent cycling life.However,performance degradation and safety issues under extreme conditions are the main challenges for the practical application.With the expansion of human activities,such as space missions,polar exploration,and so on,the investigation of SSC with wide temperature tolerance,high energy density,power density,and sustainability is highly desired.In this review,the effects of temperature on SSC are systematically illustrated and clarified,including the properties of the electrolyte,ion diffusion,and reaction dynamics of the supercapacitor.Subsequently,we summarize the recent advances in wide-temperature-range SSCs from the aspect of electrolyte modification,electrode design,and interface adjustment between electrode and electrolyte,especially with critical concerns on ionic conductivity and cycling stability.In the end,a perspective is presented,expecting to promote the practical application of the SSC in harsh conditions.

Synthesis of Porous NiO Nanocrystals with Controllable Surface Area and Their Application as Supercapacitor Electrodes

We report a facile way to grow various porous NiO nanostructures including nanoslices,nanoplates,and nanocolumns,which show a structure-dependence in their specific charge capacitances.The formation of controllable porosity is due to the dehydration and re-crystallization of β-Ni(OH)_(2) nanoplates synthesized by a hydrothermal process.Thermogravimetric analysis shows that the decomposition temperature of the β-Ni(OH)_(2) nanostructures is related to their morphology.In electrochemical tests,the porous NiO nanostructures show stable cycling performance with retention of specific capacitance over 1000 cycles.Interestingly,the formation of nanocolumns by the stacking of β-Ni(OH)_(2) nanoslices/plates favors the creation of small pores in the NiO nanocrystals obtained after annealing,and the surface area is over five times larger than that of NiO nanoslices and nanoplates.Consequently,the specific capacitance of the porous NiO nanocolumns(390 F/g)is significantly higher than that of the nanoslices(176 F/g)or nanoplates(285 F/g)at a discharge current of 5 A/g.This approach provides a clear illustration of the process-structure-property relationship in nanocrystal synthesis and potentially offers strategies to enhance the performance of supercapacitor electrodes.

An Improved Support Vector Clustering Approach to Dynamic Aggregation of Large Wind Farms

In this paper,we propose an improved support vector clustering(SVC)algorithm to cluster wind turbines(WTs)in a wind farm(WF).A boundary points(BPs)detecting method based on the grid theory and the connected subdomain(CS)are proposed.Thus the efficiency of SVC is enhanced while maintaining the accuracy of the algorithm.As for the multi-wind condition equivalent of WF,a method to determine the number and capacity of each of the aggregated wind turbines(AWTs)based on historical wind data is proposed.Only wind speed(WS)and wind direction(WD)of the WF are needed to calculate the WSs of each AWT.Results demonstrate that the algorithm proposed in this paper can cluster WTs quickly and accurately.And the dynamic aggregated models of the WFs are suitable for both the single-wind condition and multi-wind condition simulations,with high accuracy being obtained.

High-entropy alloy stabilized and activated Pt clusters for highly efficient electrocatalysis

Although Pt and other noble metals are the state-of-the-art catalysts for various energy conversion applications,their low reserve,high cost,and instability limit their large-scale utilization.Herein,we report a hybrid catalysts design featuring noble metal clusters(e.g.,Pt)uniformly dispersed and stabilized on high-entropy alloy nanoparticles(HEA,e.g.,FeCoNiCu),denoted as HEA@Pt,which is prepared via ultra-fast shock synthesis(∼300 ms)for HEA alloying combined with Pt galvanic replacement for surface anchoring.In our design,the HEA core critically ensures high dispersity,stability,and tunability of the surface Pt clusters through high entropy stabilization and core-shell interactions.As an example in the hydrogen evolution reaction,HEA@Pt achieved a significant mass activity of 235 A/gPt,which is 9.4,3.6,and 1.9-times higher compared to that of homogeneous FeCoNiCuPt(HEA-Pt),Pt,and commercial Pt/C,respectively.We also demonstrated noble Ir stabilized on FeCoNiCrMn nanoparticles(HEA-5@Ir),achieving excellent anodic oxygen evolution performance and highly efficient overall water splitting when combined with the cathodic HEA@Pt.Therefore,our work developed a general catalysts design strategies by using high entropy nanoparticles for effective dispersion,stabilization,and modulation of surface active sites,achieving a harmonious combination of high activity,stability,and low cost.

A COVID-19 Outbreak Emerging in a Food Processing Company——Harbin City,Heilongjiang Province,China,January-February 2021

Summary What is already known about this topic?The coronavirus disease 2019(COVID-19)epidemic in China had been effectively controlled for several months,but as the ambient temperature dropped,large gathering-initiated epidemics occurred in northern China,including Hebei,Liaoning,and Jilin provinces.

Stability and Accuracy Considerations in the Design and Implementation of Wind Turbine Power Hardware in the Loop Platform

There is increasing interest in the evaluation of wind turbine control capabilities for providing grid support.Power hardware in the loop(PHIL)simulation is an advanced method that can be used for studying the interaction of hardware with the power network,as the scaled-down actual wind turbine is connected with a simulated system through an amplifier.Special consideration must be made in the design of the PHIL platform to ensure that the system is stable and yields accurate results.This paper presents a method for stabilizing the PHIL interface and improving the accuracy of PHIL simulation in a real-time application.The method factors in both the power and voltage scaling level,and a phase compensation scheme.It uses the reactive power control capability of the wind turbine inverter to eliminate the phase shift imposed by the feedback current filter.This is accomplished with no negative impact on the dynamic behavior of the wind turbine.The PHIL simulation results demonstrate the effectiveness of the proposed stability analysis method and phase compensation scheme.The strength of the platform is demonstrated by extending the simulation method to wind turbine control validation.

Stereoassembled V_(2)O_(5)@FeOOH Hollow Architectures with Lithiation Volumetric Strain Self-Reconstruction for Lithium-Ion Storage

Vanadium oxides have recently attracted widespread attention due to their unique advantages and have demonstrated promising chemical and physical properties for energy storage.This work develops a mild and efficient method to stereoassemble hollow V_(2)O_(5)@FeOOH heterostructured nanoflowers with thin nanosheets.These dual-phased architectures possess multiple lithiation voltage plateau and well-defined heterointerfaces facilitating efficient charge transfer,mass diffusion,and self-reconstruction with volumetric strain.As a proof of concept,the resulting V_(2)O_(5)@FeOOH hollow nanoflowers as an anode material for lithiumion batteries(LIBs)realize high-specific capacities,long lifespans,and superior rate capabilities,e.g.,maintaining a specific capacity as high as 985 mAhg^(-1) at 200mAg^(-1) with good cyclability.

Deformable double-shelled hollow mesoporous organosilica nanocapsules:A multi-interfacial etching strategy

Multishelled hollow structures have drawn increasing interest because of their peculiar compartmentation environments and physicochemical properties.In this work,deformable double-shelled hollow mesoporous o rganosilica nanocapsules(DDHMONs)were succes s fully synthesized by a multi-interfacial etching strategy.The obtained DDHMONs have a double-shelled structure with aninorganic-organic hybrid framework,a uniform outer layer(~320 nm)and inner layer(~180 nm),ordered mesochannels(~2.21 nm),and a large specific surface area(~1233 m^(2)/g).In vitro toxicity tests show that the DDHMONs have excellent biocompatibility when coincubated with human breast cancer cells.In addition,the anti cancer substance doxorubicin(DOX)can be highly loaded in DDHMONs(~335μg/mg).The results from flow cytometry together with confocal laser scanning microscopy show that DOX can be efficiently delivered into MCF-7 cells by DDHMONs,thus improving chemotherapeutic efficiency and demonstrating that DDHMONs have potential nanomedicine applications as anticancer agents.

Incidence Tendency Analysis on Type 2 Diabetes in 4 Asian Countries—China,Malaysia,Singapore,and Thailand,1990–2019

Summary What is already known about this topic?Roughly 80%of the global disease burden caused by diabetes comes from low-and-middle income countries,and 60%of diabetics are located in Asia;6 of the top 10 countries with the highest prevalence of diabetes are in Asia.What is added by this report?Compared with 1990,the growth rate of the standardized incidence rate of type 2 diabetes in 2019 in China was significantly lower than that of the entire world,while Malaysia,Singapore.

Statistical Analysis of Articles Published in China CDC Weekly——Worldwide,2019-2020

Introduction:This study analyzed views and downloads of articles published in China CDC Weekly from 2019 to 2020 as part of an evaluation of the academic level and quality of the journal.Methods:The study included articles published between November 29,2019 and December 25,2020 and evaluated views and downloads through February 9,2021 using standard bibliometrics.We conducted network analysis with VOSviewer software.Results:There were 283 articles from 101 institutions published in China CDC Weekly during the analysis period,among which 22(21.8%)institutions were overseas institutions.There were 220 unique first authors,with 1.28 articles per first author.There were 2,404,882 views and 58,760 downloads in total.The article with the highest view and download counts had 1,244,826 views and 38,978 downloads.Article types with more than 4,500 views per article were Vital Surveillance,Notes from the Field,and Preplanned Studies.Subjects with more than 3,500 views per article were epidemiology of infectious diseases,epidemiology of non-infectious diseases,and maternal and child health.Articles with descriptive research and articles discussing public health monitoring received more attention,shown by larger average per article page views.Discussion:Study results can help the editorial department improve the journal’s international influence through targeted measures,such as adjusting article types according to view and download analyses and increasing the proportion of international manuscripts selected.