A Quaternary van der Waals Ferromagnetic Semiconductor AgVP2Se6

The recent realization of 2D magnetism in van der Waals (vdWs) magnets holds promise for future information technology. However, the vdWs semiconducting ferromagnets, which remain rare, are especially important in developing 2D magnetic devices with new functionalities due to the possibility of simultaneous control of the carrier charge and spin. Metal thiophosphate (MTP), a multifunctional vdWs material system that combines the sought‐after properties of complex oxides, is a promising vdWs magnet system. Here, single crystals of a novel vdWs ferromagnetic semiconductor MTP AgVP₂Se₆ with a room‐temperature resistivity of 1 Ω m are successfully synthesized. Due to the nature of vdWs bonding along the c‐axis, the magnetic properties of the few‐layer AgVP₂Se₆ with different thicknesses are characterized on the exfoliated samples. The AgVP₂Se₆ flakes exhibit significant thickness‐dependent magnetic properties, and a rectangular hysteresis loop with a large coercive field of 750 Oe at 2 K and an undiminished Curie temperature of 19 K are observed in the 6.7 nm AgVP₂Se₆ flake. The discovered vdWs ferromagnet AgVP₂Se₆ with semiconducting behavior will provide alternative platforms for exploring 2D magnetism and potential applications in spintronic devices.     

Achieving Rich and Active Alkaline Hydrogen Evolution Heterostructures via Interface Engineering on 2D 1T‐MoS2 Quantum Sheets

Large‐scale production of hydrogen from water‐alkali electrolyzers is impeded by the sluggish kinetics of hydrogen evolution reaction (HER) electrocatalysts. The hybridization of an acid‐active HER catalyst with a cocatalyst at the nanoscale helps boost HER kinetics in alkaline media. Here, it is demonstrated that 1T–MoS₂ nanosheet edges (instead of basal planes) decorated by metal hydroxides form highly active ${\text{edge}}_{{\text{1T‐MoS}}_{\text{2}}}$/ ${\text{edge}}_{\text{Ni}{(\text{OH})}_{\text{2}}}$ heterostructures, which significantly enhance HER performance in alkaline media. Featured with rich ${\text{edge}}_{{\text{1T‐MoS}}_{\text{2}}}$/ ${\text{edge}}_{\text{Ni}{(\text{OH})}_{\text{2}}}$ sites, the fabricated 1T–MoS₂ QS/Ni(OH)₂ hybrid (quantum sized 1T–MoS₂ sheets decorated with Ni(OH)₂ via interface engineering) only requires overpotentials of 57 and 112 mV to drive HER current densities of 10 and 100 mA cm^?2, respectively, and has a low Tafel slope of 30 mV dec^?1 in 1 m KOH. So far, this is the best performance for MoS₂‐based electrocatalysts and the 1T–MoS₂ QS/Ni(OH)₂ hybrid is among the best‐performing non‐Pt alkaline HER electrocatalysts known. The HER process is durable for 100 h at current densities up to 500 mA cm^?2. This work not only provides an active, cost‐effective, and robust alkaline HER electrocatalyst, but also demonstrates a design strategy for preparing high‐performance catalysts based on edge‐rich 2D quantum sheets for other catalytic reactions.     

Thermal Shrinkage Behavior of Metal–Organic Frameworks

Thermal treatment of metal–organic frameworks (MOFs) as a post‐treatment approach has grown in popularity and resulted in various MOF‐derived materials. However, the widely used extreme thermolytic conditions (usually above 500 °C) lead to degradation in the well‐defined MOFs intrinsic properties. This work demonstrates that MIL‐101 calcined at medium‐temperature range (200–280 °C) partially breaks the coordination bonds that can introduce more accessible active sites, exhibiting a 10‐fold increase in oxidation activity while retaining its intrinsic structure and porosity. Another fascinating feature of MIL‐101 calcined in this temperature range is their temperature‐dependent shrinkage behavior, which is also found in many other types of MOFs. Based on different shrinkage ratios of various MOFs, yolk–shell MOFs@MOFs structures can be constructed through nonsacrificial template method. Overall, the structural and morphological evolution process of MOFs treated in the medium‐temperature range can open new horizons to develop efficient MOFs catalysts and design complex structures.     

p型微晶硅薄膜的沉积及其在微晶硅薄膜太阳电池中的应用

采用等离子体化学气相沉积（PECVD）方法制备了硼掺杂微晶硅薄膜和微晶硅薄膜太阳电池.研究了乙硼烷含量、p型膜厚度及沉积温度对硼掺杂薄膜生长特性和高沉积速率的电池性能的影响.通过对p型微晶硅薄膜沉积参数的优化,在本征层沉积速率为0.78nm/s的高沉积速率下,制备了效率为5.5%的单结微晶硅薄膜太阳电池.另外,对p型微晶硅薄膜的载流子疏输运机理进行了讨论.     

基于分段PID实现永磁同步电机快速启停控制技术的研究

扫描镜常用于获取空间光电信息,应用中对其快速启停和指向精度有较高的要求。针对永磁同步电机驱动扫描镜的运动方式,建立了电机Simulink仿真模型,并采用了三闭环矢量控制策略,提出了采用分段式比例积分微分(Proportion Integration Differentiation, PID)算法进行位置环控制的方法。结果表明,相较于传统的PID,分段式PID提高了系统的响应速度,同时控制精度和稳定性也有一定提升。     

城域网中IP over DWDM的应用及发展

本文系统地阐述了IP over DWDM的分层模型、关键技术，并对IP over DWDM技术在城域网中的应用和发展前景进行了介绍。     

电大尺寸复杂结构腔体电磁散射的IPO/FEM混合法研究

该文将物理光学迭代法(IPO)的子域连接法与矢量有限元法(FEM)相结合,提出了一种新的混合方法用于分析计算电大尺寸复杂结构腔体目标的电磁散射特性。对于腔体内部适合用高频方法处理的部分采用IPO方法分析;对于具有复杂结构和材料特性的部分,采用矢量有限元法进行研究,利用交界面上的连续性条件实现这两种方法的耦合。为了验证理论模型的正确性,该文对某一矩形空腔及底部加载金属台阶的腔体进行了分析,计算结果与文献数据以及用时域有限差分法所得结果一致,并具有很好的收敛效果。在此基础上,对底部加载介质层的复杂结构腔体进行了分析计算,结果表明这种混合方法对于分析电大尺寸复杂结构腔体的散射特性是行之有效的。     

液芯波导在拉曼光谱研究中的应用及其研究进展

采用液芯波导系统进行液体样品的光谱研究具有相当高的探测灵敏度，本文对液芯波导系统在拉曼光谱中的应用及其研究进展作了比较全面的综述．分析了液芯波导系统的特点及其影响液芯波导拉曼光谱强度的主要因素及其激励采集方法、液芯波导中的光漂白效应及其对荧光背景的消除作用，以及液芯波导中的光散射机制问题，并对液芯波导的主要应用做了详细介绍．     

高阻值Cd1-xZnxTe晶体的生长及其性能测试

通过适当的工艺措施，采用Bridgman法生长了直径为30mm的X射线及γ射线探测器级的Cd.9Zn0．1Te晶锭．测试结果表明：该晶锭结晶质量良好，位错密度低，成分均匀，杂质含量低，红外透过率和电阻率都十分接近本征Cd.9Zn0．1Te的值．并从晶体的生长特性、缺陷和杂质的角度，分析了生长高性能晶体的条件，研究了生长Cdl-xZnxTe晶体的x值与缺陷和杂质浓度之间的关系．     

Impurity effects on photoluminescence in lateral epitaxially overgrown GaN

Using a two-photon laser-scanning microscope (LSM), the spectral and intensity variations of photoluminescence (PL) in a lateral epitaxially overgrown GaN film were mapped with submicron resolution. The PL results are correlated with the carrier-density variation obtained by confocal-Raman microscopy and the surface Fermi-level positions measured by scanning Kelvin-force microscopy. Near-bandgap emission spectra taken in the wing regions provide support for the previously proposed, compensated-impurity band, which arises from the incorporation of a high concentration of impurities, resulting in a carrier density of ∼10²⁰ cm⁻³.