Carbon‐encapsulated anionic‐defective MnO/Ni open microcages: A hierarchical stress‐release engineering for superior lithium storage

Rational manipulation of multicomponent materials into a sophisticated architecture is a prerequisite for developing lithium‐ion batteries.However,mechanical diffusion‐induced strain accumulation leads to sluggish diffusion kinetics and anomalous structure instability,further resulting in inferior long‐term cyclability and rate performance.Herein,the von Mises stress distribution on open microcages composed of secondary nanoparticles(OCNs)is mechanically investigated by finite element simulation,which elucidates the pronounced stress‐release effect on OCNs architecture.Afterward,a facile metal–organic framework‐derived methodology is proposed for constructing multihierarchical carbon‐encapsulated oxygen vacancy‐enriched MnO/Ni OCNs(OV‐MnO/Ni OCNs).Due to structural and compositional integration,the OV‐MnO/Ni OCNs achieve extraordinary lithium storage performance with excellent reversible capacity(1905.1 mAh g^(−1) at 0.2 A g^(−1)),ultrahigh cycling stability(1653.5 mAh g^(−1) at 2 A g^(−1) up to 600 cycles),and considerable rate capability(463.3 mAh g^(−1) even at 10 A g^(−1)).The primary lithium storage mechanisms are further systematically determined by experimental and theoretical investigations.The enriched oxygen vacancies,metallic Ni configuration,and N‐doped carbonaceous matrix provide more active sites,construct omnidirectional diffusion pathways,suppress volume expansion,and boost electronic conductivity,thus yielding an exceptional diffusivity coefficient and expedited electrochemical kinetics.This study offers profound insights for the elaborate design of multicompositional electrodes into a mechanical stress‐release structure toward advanced energy storage application and development.

Pressure-Induced Color Change in the Lutetium Dihydride LuH2

The lutetium dihydride LuH2is stable at ambient conditions.Here we show that its color undergoes sequential changes from dark blue at ambient pressure to pink at ~2.2 GPa and then to bright red at ~4 GPa upon compression in a diamond anvil cell.Such a pressure-induced color change in LuH2is reversible and it is very similar to that recently reported in the N-doped lutetium hydride [Nature 615,244(2023)].However,our preliminary resistance measurements on LuH2under pressures up to ~7 GPa evidenced no superconductivity down to 1.5 K.

针灸治疗良性前列腺增生导致的下尿路症状的系统评价和网状Meta分析

目的:良性前列腺增生引起的下尿路症状影响老年人的生活质量。在中国,针灸被应用于临床来改善由于良性前列腺增生引起的下尿路症状。缺乏证据表明哪种针灸的干预措施是最佳的选择。因此,通过比较多种针灸的临床疗效,为临床决策提供依据。方法:系统性检索了PubMed、Embase、Cochrane Library、Web of Science、中国知网、万方和维普数据库。检索时间为数据库建立到2020年7月,来寻找针灸治疗由良性前列腺增生引起下尿路症状的随机对照试验。两名研究人员进行了独立筛查和数据提取。本研究采用贝叶斯随机方法进行了网状Meta分析。使用累积排名曲线下的面积(SUCRA)来进一步评估干预措施的排名。结果:最终纳入了40篇研究,包括10种治疗方式和3,655名由良性前列腺增生引起下尿路症状的患者。在国际前列腺症状评分(MD=-3.6,95%CrI[-5.5,-1.8],极低质量证据;SUCRA=84%)、最大尿流率(MD=2.2,95%CrI[1.1,3.3],低质量证据;SUCRA=81%)和生活质量(MD=-1.395%CrI[-2.2,-0.43],极低质量证据;SUCRA=89%)方面,电针是优于其他干预措施的最佳治疗方式。结论:在所有针灸的治疗方式中,电针可能治疗由良性前列腺增生引起下尿路症状较好,伴随较少的不良事件。由于纳入研究质量的局限性,支持这一结果的证据质量为低到极低,因此需要更多高质量的随机对照试验来获得进一步的高级别证据。

Ultracompact silicon on-chip polarization controller

On-chip polarization controllers are extremely important for various optical systems.In this paper,a compact and robust silicon-based on-chip polarization controller is proposed and demonstrated by integrating a special polarization converter and phase shifters.The special polarization converter consists of a 1×1 Mach–Zehnder interferometer with two polarization-dependent mode converters at the input/output ends.When light with an arbitrary state of polarization(SOP)is launched into the chip,the TE_(0)and TM_(0)modes are simultaneously excited.The polarization extinction ratio(PER)and the phase difference for the TE_(0)∕TM_(0)modes are tuned by controlling the first phase shifter,the polarization converter,and the second phase shifter.As a result,one can reconstruct the light SOP at the output port.The fabricated polarization controller,as compact as~150μm×700μm,exhibits an excess loss of less than 1 dB and a record PER range of>54 dB for arbitrary input light beams in the wavelength range of 1530–1620 nm.

人工智能技术对就业的影响及趋势预测:基于北京市工业机器人安装量的数据

本文基于德国国际机器人联盟(IFR)统计的中国工业机器人安装量数据,利用回归模型分析检验了人工智能(AI)技术对北京市就业总量、从业人员工资水平、从业人员素质结构的影响。结果显示,北京市机器人安装量对于北京市的就业总量具有替代效应,对于从业人员的工资收入具有补偿效应,对于从业人员的素质提升则具有推动效应,而北京市三次产业增加值的增长会调节机器人安装量对就业总量的影响。运用灰色预测模型法,文章有效预测了2019-2030年北京市机器人安装量变化所引起的就业变化,并提出了相应的政策建议。

Relationship between the parent charge transfer gap and maximum transition temperature in cuprates

One of the biggest puzzles concerning the cuprate high temperature superconductors is what determines the maximum transition temperature(Tc,max), which varies from less than 30 to above 130 K in different compounds.Despite this dramatic variation, a robust trend is that within each family, the double-layer compound always has higher Tc,maxthan the single-layer counterpart. Here we use scanning tunneling microscopy to investigate the electronic structure of four cuprate parent compounds belonging to two different families. We find that within each family, the double layer compound has a much smaller charge transfer gap size(DCT), indicating a clear anticorrelation between DCTand Tc,max. These results suggest that the charge transfer gap plays a key role in the superconducting physics of cuprates, which shed important new light on the high Tc mechanism from doped Mott insulator perspective.

Toward calibration-free Mach-Zehnder switches for next-generation silicon photonics

Silicon photonic Mach–Zehnder switches(MZSs)have been extensively investigated as a promising candidate for optical systems.However,conventional 2×2 MZSs are usually prone to the size variations of the arm waveguides due to imperfect fabrication,resulting in considerable random phase imbalance between the two arms,thereby imposing significant challenges for further developing next-generation N×N MZSs.Here we propose a novel design toward calibration-free 2×2 and N×N MZSs,employing optimally widened arm waveguides,enabled by novel compact tapered Euler S-bends with incorporated mode filters.With standard 180 nm CMOS foundry processes,more than thirty 2×2 MZSs and one 4×4 Benes MZS with the new design are fabricated and characterized.Compared with their conventional counterparts with 0.45-μm-wide arm waveguides,the present 2×2 MZSs exhibit significant reduction in the random phase imbalance.The measured extinction ratios of the present 2×2 and 4×4 MZSs operating in the all-cross state are 27-49 dB and∼20dB across the wavelength range of∼60nm,respectively,even without any calibrations.This work paves the way toward calibration-free large-scale N×N MZSs for next-generation silicon photonics.