Sm–Co high-temperature permanent magnet materials

Permanent magnets capable of reliably operating at high temperatures up to ~450?C are required in advanced power systems for future aircrafts, vehicles, and ships. Those operating temperatures are far beyond the capability of Nd–Fe–B magnets. Possessing high Curie temperature, Sm–Co based magnets are still very important because of their hightemperature capability, excellent thermal stability, and better corrosion resistance. The extensive research performed around the year 2000 resulted in a new class of Sm_2(Co, Fe, Cu, Zr)_(17)-type magnets capable of operating at high temperatures up to 550?C. This paper gives a systematic review of the development of Sm–Co permanent magnets, from the crystal structures and phase diagrams to the intrinsic magnetic properties. An emphasis is placed on Sm_2(Co, Fe, Cu, Zr)_(17)-type magnets for operation at temperatures from 300?C to 550?C. The thermal stability issues, including instantaneous temperature coefficients of magnetic properties, are discussed in detail. The significance of nanograin structure, nanocrystalline, and nanocomposite Sm–Co magnet materials, and prospects of future rare-earth permanent magnets are also given.

Study about thermal runaway behavior of high specific energy density Li-ion batteries in a low state of charge

Lithium-ion batteries are widely used in electric vehicles and electronics, and their thermal safety receives widespread attention from consumers. In our study, thermal runaway testing was conducted on the thermal stability of commercial lithium-ion batteries, and the internal structure of the battery was analyzed with an in-depth focus on the key factors of the thermal runaway. Through the study of the structure and thermal stability of the cathode, anode, and separator, the results showed that the phase transition reaction of the separator was the key factor affecting the thermal runaway of the battery for the condition of a low state of charge.

Identification and Characterization of Tonoplast Sugar Transporter (TST) Gene Family in Cucumber

Tonoplast sugar transporters(TSTs)play essential roles in regulating plant growth,development,and response to various biotic and abiotic stresses.In this study,a total of three TST genes were identified by a genome-wide analysis in cucumber.Phylogenetic analysis showed that TST proteins from cucumber and other plant species can be classified into five groups,and nearly all TST members in the same groups displayed similarmotif distributions,transmembrane(TM)domains,and gene structures.All of the three CsTST genes possess a number of development-,stress-,and hormone-related cis-elements in the promoter sequences.Meanwhile,qRT-PCR assays revealed that the CsTST1 was expressed in fruits,flowers,leaves,and other tissues,and its expression varied significantly under various abiotic stresses such as cold,salt,drought(PEG),and abscisic acid(ABA).Finally,functional analysis of CsTST1 in yeast revealed that it was able to complement the deficiency in galactose,mannose and sucrose transport.These results revealed that CsTST1 can act as a functional sugar transporter to play important roles in cucumber growth and response to abiotic stress probably through affecting carbohydrate distribution.

聚丙烯的阻燃改性及其用于包装材料的研究进展

聚丙烯(PP)作为五大通用塑料之一,在各行各业中都有着广泛的应用,然而PP易燃的特点也限制了其应用空间,阻碍了PP材料的进一步发展,因此PP的阻燃改性一直是人们关注的重点。本文介绍了不同阻燃剂的改性方法及其优缺点,分析了各种阻燃剂的阻燃机理,并总结了近年来阻燃PP的研究现状与进展,同时对阻燃聚丙烯材料在包装领域的应用进行了展望。

Study on influencing factors of ion current density measurement in corona discharge of HVDC transmission lines

The ground level ion current density produced by corona discharge in high voltage direct current(HVDC)transmission lines can reflect the operation status of the lines,but the distorted electric field at the edge of the Wilson plate seriously affects the measurement results of ion current density.In order to measure the ground level ion current density accurately and directly,a new reduced scale wire-plate experimental device in which the Wilson plate is flush with the grounding plate is designed.The influence of protective annulus width and the height of the Wilson plate from the grounding plate on ground level ion current density are studied.In addition,the differences between the micro-current galvanometer method and the sampling resistance method in the measurement of ion current density are compared.Finally,the ground level ion current density distributions of unipolar and bipolar HVDC transmission lines are measured.The results show that the edge effect of the Wilson plate can be neglected when the width of protective annulus is less than 2 mm,and the ion current density is nonlinear with the height of the Wilson plate from the grounding plate.Moreover,the internal resistance of the digital voltmeter seriously affects the measurement results and it is necessary to correct the results.Finally,at the same applied voltage,the ground level ion current density in the negative conductor region is higher than that in the positive conductor region.

Research on corona discharge suppression of high-voltage direct-current transmission lines based on dielectric-film-covered conductor

Corona discharge suppression for high-voltage direct-current(HVDC)transmission lines at line terminals such as converter stations is a subject that requires attention.In this paper,a method based on a conductor covered with dielectric film is proposed and implemented through a bench-scale setup.Compared with the bare conductor,the corona discharge suppression effect of the dielectric-film-covered conductor under positive polarity is studied from the composite field strength and ion current density using a line-plate experimental device.The influences of film thickness and film material on the corona discharge suppression effect are investigated.The charge accumulation and dissipation characteristics of different film materials are also studied.The results show that the conductor covered with dielectric film has excellent ability to inhibit corona discharge.The ground-level composite field strength of the conductor covered with dielectric film is lower than its nominal field strength,and its ion current density is at the nA m^(−2) level.The corona threshold voltage can be promoted by increasing the film thickness,but the ability to inhibit corona discharge becomes weak.The larger the surface electric field strength,the more charge accumulated,but the faster the charge dissipation rate.Compared with polyvinyl chloride film,cross-linked polyethylene film has stronger charge accumulation ability and slower charge dissipation rate,which can better restrain the corona discharge of HVDC transmission lines.

Tuning the Surface Field by Embedding Cations into Metals to Direct the Reaction Pathway of CO_(2) Electroreduction

The creation of universal strategies to affect the reaction route of the electroreduction of CO_(2) is critical.Here,we report the first work to introduce cations into diverse metals such as Cu,Bi,In,and Sn via the electroreduction of related metallic oxides in quaternary ammonium surfactant solutions.Compared to their physical adsorption,cations embedded into the electrodes have a more pronounced impact on the electrical field,which effectively influences the adsorption state of intermediates.With the increase of surface field,the hydrogen evolution reaction and*COOH route are significantly reduced,favouring the*OCHO pathway instead.As a result,hydrogen,CO,and C_(2+)products almost completely vanish at−0.5 V versus RHE in 0.1 M Na_(2)SO_(4)in an H-type cell after enough cations are embedded into the Cu electrode,and the faradaic efficiency of formate rises from 18.0%to 99.5%simultaneously.

Wearable Leg Movement Monitoring System for High-Precision Real-Time Metabolic Energy Estimation and Motion Recognition

Comprehensive and quantitative assessment of human physical activity in daily life is valuable for healthcare,especially for those who suffer from obesity and neurological disorders or are at high risk of dementia.Common wearable devices,e.g.,smartwatches,are insufficient and inaccurate for monitoring highly dynamic limb movements and assessing human motion.Here,we report a new wearable leg movement monitoring system incorporating a custom-made motion sensor with machine learning algorithm to perceive human motion accurately and comprehensively during diverse walking and running actions.The system enables real-time multimodal perceptions of personal identity,motion state,locomotion speed,and energy expenditure for wearers.A general law of extracting real-time metabolic energy from leg movements is verified although individual gaits show differences.In addition,we propose a novel sensing configuration combining unilateral lower leg movement velocity with its angular rate to achieve high accuracy and good generalizability while simplifying the wearable system.Advanced performances in personal identification(accuracy of 98.7%)and motion-state recognition(accuracy of 93.7%)are demonstrated.The wearable system also exhibites high-precision real-time estimations of locomotion speed(error of 3.04%to 9.68%)and metabolic energy(error of 4.18%to 14.71%)for new subjects across various time-varying conditions.The wearable system allows reliable leg movement monitoring and quantitative assessment of bodily kinematic and kinetic behaviors during daily activities,as well as safe identity authentication by gait parameters,which would greatly facilitate smart life,personal healthcare,and rehabilitation training.

Cardiac fibroblast heat shock protein 47 aggravates cardiac fibrosis post myocardial ischemia-reperfusion injury by encouraging ubiquitin specific peptidase 10 dependent Smad4 deubiquitination

Despite complications were significantly reduced due to the popularity of percutaneous coronary intervention(PCI) in clinical trials, reperfusion injury and chronic cardiac remodeling significantly contribute to poor prognosis and rehabilitation in AMI patients. We revealed the effects of HSP47 on myocardial ischemia-reperfusion injury(IRI) and shed light on the underlying molecular mechanism.We generated adult mice with lentivirus-mediated or miRNA(mi1/133TS)-aided cardiac fibroblastselective HSP47 overexpression. Myocardial IRI was induced by 45-min occlusion of the left anterior descending(LAD) artery followed by 24 h reperfusion in mice, while ischemia-mediated cardiac remodeling was induced by four weeks of reperfusion. Also, the role of HSP47 in fibrogenesis was evaluated in cardiac fibroblasts following hypoxia-reoxygenation(HR). Extensive HSP47 was observed in murine infarcted hearts, human ischemic hearts, and cardiac fibroblasts and accelerated oxidative stress and apoptosis after myocardial IRI. Cardiac fibroblast-selective HSP47 overexpression exacerbated cardiac dysfunction caused by chronic myocardial IRI and presented deteriorative fibrosis and cell proliferation.HSP47 upregulation in cardiac fibroblasts promoted TGFβ1-Smad4 pathway activation and Smad4 deubiquitination by recruiting ubiquitin-specific peptidase 10(USP10) in fibroblasts. However, cardiac fibroblast specific USP10 deficiency abolished HSP47-mediated fibrogenesis in hearts. Moreover, blockage of HSP47 with Col003 disturbed fibrogenesis in fibroblasts following HR. Altogether, cardiac fibroblast HSP47 aggravates fibrosis post-myocardial IRI by enhancing USP10-dependent Smad4 deubiquitination,which provided a potential strategy for myocardial IRI and cardiac remodeling.

Field Simulation of Aerosol Transmission of SARS-CoV-2 in a Special Building Layout—Guangdong Province,China,2021

What is already known on this topic?Aerosol transmission was one route for the spread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and usually occurred in confined spaces.What is added by this report?Aerosol transmission was found to exist between handshake buildings,i.e.,buildings with extremely close proximity that formed relatively enclosed spaces.Transmission was mainly affected by the airflow layout caused by switching air conditioners on and off as well as opening and closing doors and windows.What are the implications for public health practice?Centralized isolation and home isolation in handshake buildings creates a risk of SARS-CoV-2 aerosol transmission under certain conditions.Attention should be paid to the influence of air distribution layout on aerosol diffusion in isolation wards,and disinfection of isolation venues should be strengthened.

Minimizing makespan of a production batch within concurrent systems:Seru production perspective

This paper discusses the makespan minimization of a production batch within a specific concurrent system,seru production system.A seru production system consists of multiple independent serus.A seru is a compact assembly origination in which products are assembled from-the-beginning-to-the-end without disruptions.One capability of a seru production system is its responsiveness.A performance measure used to evaluate a seru system’s responsiveness is the makespan of production batches assembled within the seru system.This study addresses the makespan minimization problem through an optimal seru loading policy.The problem is formulated as a min-max integer optimization model.An exact dimension-reduction Algorithm is developed to obtain the optimal allocation that minimizes the makespan.We show that the solution space increases very quickly.In contrast,our algorithm is efficient with a polynomial computational complexity of,where is the total number of serus in a seru system.To verify the usefulness of the developed exact dimension-reduction algorithm,we compare it with a widely practiced greedy algorithm through experiments.We find that our optimal algorithm is robust in most cases and the greedy algorithm is efficient when variability in production efficiencies is high.This result can guide us to adopt different algorithms in different business environments.If the variability in production efficiencies is high,e.g.,new employees and/or new products assembly,the greedy algorithm is efficient.For other cases,our optimal algorithm should be adopted to obtain the minimum makespan.We also extend the method to the application of a rotating seru.

Comparative Study on Traction Battery Charging Strategies from the Perspective of Material Structure

The service life of an electric vehicle is,to some extent,determined by the life of the traction battery.A good charging strat-egy has an important impact on improving the cycle life of the lithium-ion battery.Here,this paper presents a comparative study on the cycle life and material structure stability of lithium-ion batteries,based on typical charging strategies currently applied in the market,such as constant current charging,constant current and constant voltage charging,multi-stage constant current charging,variable current intermittent charging,and pulse charging.Compared with the reference charging strategy,the charging capacity of multi-stage constant current charging reaches 88%.Moreover,the charging time is reduced by 69%,and the capacity retention rate after 500 cycles is 93.3%.Through CT,XRD,SEM,and Raman spectroscopy analysis,it is confirmed that the smaller the damage caused by this charging strategy to the overall structure of the battery and the layered structure and particle size of the positive electrode material,the higher the capacity retention rate is.This work facilitates the development of a better charging strategy for a lithium-ion battery from the perspective of material structure.