Pathfinding Pulsar Observations with the CVN Incorporating the FAST

The importance of Very Long Baseline Interferometry(VLBI)for pulsar research is becoming increasingly prominent and receiving more and more attention.We present the pathfinding pulsar observation results with the Chinese VLBI Network(CVN)incorporating the Five-hundred-meter Aperture Spherical radio Telescope(FAST).On MJD 60045(11th April 2023),PSRs B0919+06 and B1133+16 were observed with the phase-referencing mode in the L-band using four radio telescopes(FAST,TianMa,Haoping,and Nanshan)and correlated with the pulsar binning mode of the distributed FX-style software correlator in Shanghai.After further data processing with the NRAO Astronomical Image Processing System(AIPS),we detected these two pulsars and fitted their current positions with accuracy at the milliarcsecond level.By comparison,our results show significantly better agreement with predicted values based on historical VLBI observations than those with previous timing observations,as pulsar astrometry with the VLBI provides a more direct and model-independent method for accurately obtaining related parameters.

基于聚碳酸丙烯酯基聚合物电解质和有机正极的全固态钠电池

聚碳酸酯具有较高的介电常数和较强极性的碳酸酯基团,是一类高性能的聚合物固态电解质,但是它在全固态钠离子电池体系中的研究非常少。本文以简便的方法成功制备出了聚碳酸丙烯酯基全固态聚合物电解质,并研究了该全固态电解质在以3,4,9,10-苝四甲酸二酐为正极的有机全固态钠电池中的应用。这种全固态聚合物电解质在钠离子电池中的应用能够有效提高钠离子电池的安全性,防止过充、电解液泄露甚至爆炸等一系列不安全因素带来的隐患。结果表明:这种聚碳酸丙烯酯基全固态聚合物电解质在室温下具有较高的电导率,并且循环前后的阻抗测试说明了该电解质与有机正极具有良好的兼容性。取代了传统液体有机电解液后,该全固态钠电池在室温下展示出了优异的循环性能,循环50周后,容量保持率为99.1%;然而,同类型的液体电池遭受了严重的容量衰减,循环50周后容量只有24.6 mAh·g^−1,容量保持率仅为20.5%。

Copper‑Based Catalysts for Electrochemical Carbon Dioxide Reduction to Multicarbon Products

Electrochemical conversion of carbon dioxide into fuel and chemicals with added value represents an appealing approach to reduce the greenhouse effect and realize a carbon-neutral cycle,which has great potential in mitigating global warming and effectively storing renewable energy.The electrochemical CO_(2) reduction reaction(CO_(2)RR)usually involves multiproton coupling and multielectron transfer in aqueous electrolytes to form multicarbon products(C_(2+) products),but it competes with the hydrogen evolution reaction(HER),which results in intrinsically sluggish kinetics and a complex reaction mechanism and places higher requirements on the design of catalysts.In this review,the advantages of electrochemical CO_(2) reduction are briefly introduced,and then,different categories of Cu-based catalysts,including monometallic Cu catalysts,bimetallic catalysts,metal-organic frameworks(MOFs)along with MOF-derived catalysts and other catalysts,are summarized in terms of their synthesis method and conversion of CO_(2) to C2+products in aqueous solution.The catalytic mechanisms of these catalysts are subsequently discussed for rational design of more efficient catalysts.In response to the mechanisms,several material strategies to enhance the catalytic behaviors are proposed,including surface facet engineering,interface engineering,utilization of strong metal-support interactions and surface modification.Based on the above strategies,challenges and prospects are proposed for the future development of CO_(2)RR catalysts for industrial applications.

Iaso： an autonomous fault-tolerant management system for supercomputers

With the increase of system scale, the inherent reliability of supercomputers becomes lower and lower. The cost of fault handling and task recovery increases so rapidly that the reliability issue will soon harm the usability of supercomputers. This issue is referred to as the ＂reliability wall＂, which is regarded as a critical problem for current and future supercomputers. To address this problem, we propose an autonomous fault-tolerant system, named Iaso, in MilkyWay- 2 system. Iaso introduces the concept of autonomous management in supercomputers. By autonomous management, the computer itself, rather than manpower, takes charge of the fault management work. Iaso automatically manage the whole lifecycle of faults, including fault detection, fault diagnosis, fault isolation, and task recovery. Iaso endows the autonomous features with MilkyWay-2 system, such as self-awareness, self-diagnosis, self-healing, and self-protection. With the help of Iaso, the cost of fault handling in supercomputers reduces from several hours to a few seconds. Iaso greatly improves the usability and reliability of MilkyWay-2 system.

Compressible and Lightweight MXene/Carbon Nanofiber Aerogel with “Layer‑Strut” Bracing Microscopic Architecture for Efficient Energy Storage

Two-dimensional MXene has recently captured widespread research attention in energy storage and conversion fields due to its high conductivity,large specific surface area,and remarkable electro-activity.However,its performance is still hindered by severe self-restacking of MXene flakes.Herein,conductive Ti_(3)C_(2)T_(x)/carbon nanofiber(CNF)composite aerogel with typical“layer-strut”bracing 3D microscopic architecture has been fabricated via synergistic assembly and freeze-drying process.In virtu of the strong interfacial interaction between polymeric precursor nanofibers and MXene mono-layers,gelation capability and 3D formability of Ti_(3)C_(2)T_(x) is greatly reinforced,as resulted Ti_(3)C_(2)T_(x)/CNF aerogels possess a highly ordered microporous structure with interlayered CNF penetrating between large size MXene lamellae.This special configuration guarantees the stability and pliability of the composite aerogels.Furthermore,the 3D form interconnected conductive network and the parallell alignment of the pores allow free electrical carriers motion and ion migration.As a result,the prepared Ti_(3)C_(2)T_(x)/CNF aerogel-based electrode exhibits an exceptional gravimetric specific capacitance of 268 F g^(−1) at a current density of 0.5 A g^(−1) and an excellent cycling stability of 8000 cylcles,and the assembled symmetric supercapacitor,delivers a high energy density of 3.425 W h kg^(−1) at 6000 W kg^(−1).This work offers a new route for the rational construction of 3D MXene assembly for advanced energy storage materials.