Pressure-induced growth of coralloid-like FeF_(2) nanocrystals to enable high-performance conversion cathode

Fluoride ferrous(FeF_(2))is viewed as a promising conversion cathode material for next-generation lithiumion batteries(LIBs)due to its high theoretical specific capacity and low cost.Unfortunately,issues such as poor intrinsic conductivity,iron dissolution,and phase separation hinder the application of FeF_(2)in highenergy cathodes.Here,a pressure-induced morphology control method is designed to prepare coralloidlike FeF_(2)nanocrystals with nitrogen-rich carbon coating(c-FeF_(2)@NC).The coralloid-like interconnected crystal structure of c-FeF_(2)@NC contributes to reducing interfacial resistance and enhancing the topotactic transformation during the conversion reaction,and the nitrogen-rich carbon(NC)coating can enhance interfacial stability and kinetic performance.When used as a conversion cathode for LIBs,c-FeF_(2)@NC exhibits a high initial reversible capacity of 503.57 mA h g^(-1)and excellent cycling stability of497.61 m A h g^(-1)with a low capacity decay of 1.19%over 50 cycles at 0.1 A/g.Even at 1 A/g,a stable capacity of 263.78 mA h g^(-1)can still be retained after 200 cycles.The capability of c-FeF_(2)@NC as a conversion cathode for sodium-ion batteries(SIBs)was also evaluated to expand its field of application.Furthermore,two kinds of full batteries have been assembled by employing c-FeF_(2)@NC as cathodes and quantitative limited-Li(LLi)and pre-lithiated reduced graphene oxide(PGO)as anodes,respectively,to envisage the feasibility of practical applications of conversion materials.

Robust optimization for volume variation in timber processing

Volume variation is an uncertainty element which affects timber processing. We studied the volume variation of logs caused by quality defects in traditional timber processing and set up an optimization approach,using a robust optimization method. We used total number of acceptable boards produced to study the relationship between board thickness and raw material logs, using a heuristic search algorithm to control the variation of board volume to improve the output of boards, reduce the quantity of by-products, and lower production costs. The robust optimization method can effectively control the impact of volume variations in timber processing, reduce cutting waste as far as possible using incremental processing and increase profits, maximize the utilization ratio of timber, prevent waste in processing, cultivate the productive type of tree species and save forest resources.

Study on the Personal Submission of Agricultural Product Samples for Quality and Safety Inspection

This paper carries out a questionnaire survey on 30 quality inspection institutions at the level of the Ministry of Agriculture,and based on systematic analysis,analyzes the causes of difficulties in personal submission of samples for inspection from six aspects in order to meet the real needs of personal submission of agricultural product samples for inspection under the new situation. In accordance with the actual situation of China's current regulatory system and quality control system,this paper sets forth the relevant recommendations to correctly guide the personal submission of samples for inspection and promote the development of quality inspection system.

Flash-assisted doping graphene for ultrafast potassium transport

Graphene has been widely used for electrical energy storage and its performances could be further improved by heteroatom doping.How to prepare doped graphene efficiently and economically remains a significant challenge.Here,we propose a flash-assisted doping method to produce nitrogen-and sulfur-doped graphene(N-rGO and S-rGO).Using this method,graphene oxide(GO)is reduced to few-layer graphene(rGO)in seconds without the use of reductants,accompanied with a high doping efficiency.Particularly,the as-synthesized N-rGO with a high N content of 12.75 at.%used as potassium-ion battery(KIB)anode exhibits ultrafast K+-transport kinetics and superior K^(+)-storage capability.Quantitative kinetics analysis and theoretical simulation are used to reveal the mechanism of transportation and storage of K^(+)in N-rGO.

Recent progress in organic color-tunable phosphorescent materials

Organic color-tunable phosphorescent materials depend upon multiple emission centers to achieve colortunable phosphorescence with changes in excitation wavelength,temperature,time,and other external factors.Organic color-tunable phosphorescent materials are becoming increasingly popular due to their potential applications in anticounterfeiting,encryption and sensing.This brief review focuses on the formation of multiple emission centers in organic color-tunable phosphorescent materials and how to ensure that these multiple emission centers can simultaneously emit.In the future,materials with a large color tunable ranges,increased efficiency,and relatively long lives will be developed.

The effect of Coulomb interaction on particle-antiparticle correlation function

Dear Editors,The quantitative interpretation of the particle and antiparticle correlation results depends critically on understanding the role of Coulomb interaction of the measured pairs of particles with each other,as well as the Coulomb interaction of the pair with the system of remaining particles[1-7].

A digital lightning prototype system: DLPS/HUST

Digital lightning is an important thematic branch of the digital earth.Lightning data are complex,momentary,discrete,dynamic and spatio-temporal in nature.Hence,making great progress in their management,analysis and service is challenging.Many studies have been directed towards this field all over the world.Some different relevant systems are currently available.However,most of them focus on a single or a few aspects of lightning applications,rather than taking an overall account of lightning detection,management,analysis and service from the strategic perspective of the digital earth.Lightning disaster also demands a better developed spatial information technology in this field than at present.The idea of the digital earth offers a reasonable scheme to address these issues.Based on reviews of the concept,development and progress of the digital earth,an integrated technical framework of a digital lightning prototype system(DLPS)is proposed,including its data,functions and implementation of subsystems,which aims at the facilitation,management,accessing,visualisation,application,release and sharing of lightning data.Some key technologies are also carefully discussed to facilitate the construction of the DLPS.This framework could provide a helpful guide to future lightning research and hazard mitigation,as well as enrich connotation on the digital earth.So far,there are still many difficulties in multilevel grid construction that need to be solved.

Development of optimal speed trajectory control strategy for electric vehicles to suppress battery aging

In order to suppress the battery aging of electric vehicles(EVs),a multi-objective optimization function is established to describe the battery aging behavior based on a high-precision battery aging model,and the state–space equation is then constructed to reveal the intrinsic relationship between vehicle speed,acceleration,and battery state-of-charge(SOC).The constructed optimization model is solved by using a sequential quadratic programming(SQP)algorithm,and based on the model predictive control(MPC)theory,the efficient real-time control of vehicle speed is achieved.Simulation results show that the developed strategy extends the battery life by 10.33%compared to the baseline strategy when the traffic flow is not involved.In the case of involving the traffic flow,the optimization results of battery aging improves as the look-ahead time period increases,while the computational burden increases.The results show that the developed strategy reduces the battery aging of the target vehicle by 33.02%compared to the preceding vehicle while meeting the real-time requirement.