Achieving long-cycling sodium-ion full cells in ether-based electrolyte with vinylene carbonate additive

Application of sodium-ion batteries is suppressed due to the lack of appropriate electrolytes matching cathode and anode simultaneously.Ether-based electrolytes,preference of anode materials,cannot match with high-potential cathodes failing to apply in full cells.Herein,vinylene carbonate(VC)as an additive into NaCF_(3) SO_(3)-Diglyme(DGM)could make sodium-ion full cells applicable without preactivation of cathode and anode.The assembled FeS@C||Na3 V2(PO_(4))_(3)@C full cell with this electrolyte exhibits long term cycling stability and high capacity retention.The deduced reason is additive VC,whose HOMO level value is close to that of DGM,not only change the solvent sheath structure of Na^(+),but also is synergistically oxidized with DGM to form integrity and consecutive cathode electrolyte interphase on Na3 V2(PO_(4))_(3)@C cathode,which could effectively improve the oxidative stability of electrolyte and prevent the electrolyte decomposition.This work displays a new way to optimize the sodium-ion full cell seasily with bright practical application potential.

A New Position Calibration Method for MUSER Images

The Mingantu Spectral Radioheliograph(MUSER),a new generation of solar dedicated radio imagingspectroscopic telescope,has realized high-time,high-angular,and high-frequency resolution imaging of the Sun over an ultra-broadband frequency range.Each pair of MUSER antennas measures the complex visibility in the aperture plane for each integration time and frequency channel.The corresponding radio image for each integration time and frequency channel is then obtained by inverse Fourier transformation of the visibility data.However,the phase of the complex visibility is severely corrupted by instrumental and propagation effects.Therefore,robust calibration procedures are vital in order to obtain high-fidelity radio images.While there are many calibration techniques available—e.g.,using redundant baselines,observing standard cosmic sources,or fitting the solar disk—to correct the visibility data for the above-mentioned phase errors,MUSER is configured with non-redundant baselines and the solar disk structure cannot always be exploited.Therefore it is desirable to develop alternative calibration methods in addition to these available techniques whenever appropriate for MUSER to obtain reliable radio images.In the case where a point-like calibration source contains an unknown position error,we have for the first time derived a mathematical model to describe the problem and proposed an optimization method to calibrate this unknown error by studying the offset of the positions of radio images over a certain period of the time interval.Simulation experiments and actual observational data analyses indicate that this method is valid and feasible.For MUSER’s practical data the calibrated position errors are within the spatial angular resolution of the instrument.This calibration method can also be used in other situations for radio aperture synthesis observations.

通过从头算非绝热分子动力学研究1T-VSe_(2)中的光激发诱导自旋动力学

利用光激发来操控二维材料中的磁矩是实现光自旋电子学器件的基础.本工作中,我们利用从头算非绝热分子动力学模拟,研究了光激发如何改变二维铁磁金属VSe_(2)中的磁矩.我们发现自旋-轨道耦合作用和声子激发导致了自旋向上和自旋向下电子态发生混合,并在费米能级以上1.0 eV附近形成了一个自旋混合区.当自旋向上或向下的电子在弛豫过程中经过这个混合区时,它们会丢失原有的自旋方向.当电子从费米面以上2.0 eV左右向下弛豫时,自旋向下的电子发生带内弛豫,而自旋向上的电子发生带间弛豫.因此,自旋向下电子的弛豫速度比自旋向上电子高出约一个数量级.这种自旋向上和自旋向下电子的动态行为差异导致了VSe_(2)的磁矩在光激发后10 fs内先增大,这对应了自旋向下电子失去了原始的自旋方向;随后,磁矩在100 fs内减小,这对应了自旋向上电子失去了原始自旋的方向;最后,系统的总磁矩在皮秒的时间尺度内逐渐恢复到光激发前的水平.这项工作为我们了解光激发如何操控二维材料的磁性提供了理论依据.

太阳极轨天文台

太阳极轨天文台利用高轨道倾角(≥80°)和小椭偏率轨道,将首次实现正面对太阳极区磁场和速度场高精度成像观测,结合多波段遥感和原位测量,为解决太阳磁活动周起源的世纪难题提供决定性观测,为破解“原始”高速太阳风的起源效应之谜提供直接观测支撑,为理解日球层整体结构突破性创建数据驱动的日球数值模型.

Engineered high-strength biohydrogel as a multifunctional platform to deliver nucleic acid for ameliorating intervertebral disc degeneration

Intervertebral disc degeneration(IVDD)is a leading cause of low back pain.The strategy of using functional materials to deliver nucleic acids provides a powerful tool for ameliorating IVDD.However,the immunogenicity of nucleic acid vectors and the poor mechanical properties of functional materials greatly limit their effects.Herein,antagomir-204-3p(AM)shows low immunogenicity and effectively inhibits the apoptosis of nucleus pulposus cells.Moreover,a high-strength biohydrogel based on zinc-oxidized sodium alginate-gelatin(ZOG)is designed as a multifunctional nucleic acid delivery platform.ZOG loaded with AM(ZOGA)exhibits great hygroscopicity,antibacterial activity,biocompatibility,and biodegradability.Moreover,ZOGA can be cross-linked with nucleus pulposus tissue to form a high-strength collagen network that improves the mechanical properties of the intervertebral disc(IVD).In addition,ZOGA provides an advantageous microenvironment for genetic expression in which AM can play an efficient role in maintaining the metabolic balance of the extracellular matrix.The results of the radiological and histological analyses demonstrate that ZOGA restores the height of the IVD,retains moisture in the IVD,and maintains the tissue structure.The ZOGA platform shows the sustained release of nucleic acids and has the potential for application to ameliorate IVDD,opening a path for future studies related to IVD.

PAANa粘结剂诱导形成柔韧固态电解质膜提升微米级FeS电极的储钠性能

高容量金属硫化物面临着首周库伦效率低、穿梭效应和体积膨胀等导致的严重容量衰退问题,碳包覆和固定常被用来解决上述问题.然而,这些方法通常比较复杂、耗时,不利于大规模应用.本文提出一种采用粘结剂优化解决微米级FeS电极材料上述问题的简便策略,以极性聚合物粘结剂聚丙烯酸钠(PAANa)为例,研究了其作用机制:PAANa粘结剂的引入可与FeS材料颗粒形成交联的网状结构,既可以缓冲电极材料在充放电时体积的改变所产生的机械应力,还诱导并参与在FeS颗粒表面形成较薄的SEI膜,提高了电极界面离子迁移速度和电极的首周库伦效率,使得FeS负极的循环稳定性和倍率性能得到明显优化.本工作不仅使人们对电极粘结剂在电极中的作用有了新的认识,而且为优化电池材料性能提供了新途径.