Layered Transition Metal Electride Hf2Se with Coexisting Two-Dimensional Anionic d-Electrons and Hf–Hf Metallic Bonds

Electrides are unique materials,whose anionic electrons are confined to interstitial voids,and they have broad potential applications in various areas.In contrast to the majority of inorganic electrides,in which the anionic electrons primarily consist of s-electrons of metals,electrides with anionic d-electrons are very rare.Based on first-principles electronic structure calculations,we predict that the layered transition metal chalcogenide Hf₂Se is a novel electride candidate with anionic d-electrons.Our results indicate that the anionic electrons confined in the Hf₆ octahedra vacancy between [Hf₂Se] layers mainly come from the Hf-5 d orbitals.In addition,the anionic electrons coexist with the Hf-Hf multiple-center metallic bonds located in the center of neighboring Hf₄ tetrahedra.The calculated work function(3.33 eV) for the(110) surface of Hf₂Se is slightly smaller than that of Hf₂S,which has recently been reported to exhibit good electrocatalytic performance.Our study of Hf2 Se will enrich the electride family,and promote further research into the physical properties and applications of electrides.     

一种适用于能量收集系统的低功耗张弛振荡器

为满足微小能量收集系统的低电压、低功耗应用需求,设计了一种低温度系数的低功耗、小面积的张弛振荡器。使用自偏置Cascode复合晶体管结构分别代替传统倍增电流偏置电路中的大电阻和振荡器核心电路中在比较器输入端生成电压参考的大电阻,实现低功耗,同时达到减小电路面积,提高集成度的目的。采用0.18μm CMOS工艺进行设计,仿真结果表明,该振荡器可在0.8～1.2 V的电源电压下正常工作,在工作频率为2.2 kHz时,功耗为30 nW,工作频率的温度系数TC可达1.03×10^-4/℃,芯片面积相对于同类电路至少减小了70%。     

Tuning of Magnetic Properties of α-RuCl3 Single Crystal by Cr Doping

We study the influence of Cr doping on magnetic properties of α-RuCl₃ single crystals in detail.With increasing Cr content,the c-axial lattice parameter increases gradually,implying that the Cr doping may weaken the interlayer interactions.The magnetism of Ru_1-xCr_xCl₃ single crystals evolves from a long-range AFM order to a possible spin-glass state with Cr doping.The appearance of a possible spin-glass state can be explained by the introduction of FM ...     

我国网商发展的区域差异及协调发展对策

为了明确网商发展的区域差异,选择标准差、变异系数与地理集中指数分析网商发展的省际差异,运用泰尔指数将网商发展总体差异分解为东、中、西部三大地区的区内差异与区际差异。结果表明,我国网商发展综合指数的省际差异呈下降趋势,网商发展综合指数的区内差异是西部地区最大、东部地区其次、中部地区最小,在网商发展综合指数的总体差异中,贡献最大的是西部地区区内差异,其次是东部地区区内差异,然后是区际差异,中部地区区内差异的贡献最小。根据区域协调发展原则与分析结果,探讨了三大地区及相对落后省市的网商协调发展对策。