Proximity-Induced Fully Ferromagnetic Order with Eightfold Magnetic Anisotropy in Heavy Transition Metal Oxide CaRuO3

Ferromagnetic materials with a strong spin-orbit coupling (SOC) have attracted much attention in recent years because of their exotic properties and potential applications in energy-efficient spintronics. However, such materials are scarce in nature. Here, a proximity-induced paramagnetic to ferromagnetic transition for the heavy transition metal oxide CaRuO₃ in (001)-(LaMnO₃/CaRuO₃) superlattices is reported. Anomalous Hall effect is observed in the temperature range up to 180 K. Maximal anomalous Hall conductivity and anomalous Hall angle are as large as ∼15 Ω⁻¹ cm⁻¹ and ∼0.93%, respectively, by one to two orders of magnitude larger than those of the typical 3d ferromagnetic oxides such as La_0.67Sr_0.33MnO₃. Density functional theory calculations indicate the existence of avoid band crossings in the electronic band structure of the ferromagnetic CRO layer, which enhances Berry curvature thus strong anomalous Hall effects. Further evidences from polarized neutron reflectometry show that the CaRuO₃ layers are in a fully ferromagnetic state (∼0.8 μ_B/Ru), in sharp contrast to the proximity-induced canted antiferromagnetic state in 5d oxides SrIrO₃ and CaIrO₃ (∼0.1 μ_B/Ir). More than that, the magnetic anisotropy of the (001)-(LaMnO₃/CaRuO₃) superlattices is eightfold symmetric, showing potential applications in the technology of multistate data storage.     

Freely Tailorable Yolk-Shell Encapsulation: Versatile Applications in Ultralow-k Dielectric,Drug Delivery Systems,and Catalysts

Herein, a facile, controllable, and versatile method is reported to prepare monodisperse yolk-shell and yolk-multishell silica nanoparticles (NPs) with mesoporous shells by a novel selective etching strategy. The mechanism of selective etching based on fluoride-silica chemistry is investigated in detail and thus provides a fundamentally novel principle for the fabrication of yolk-shell NPs. Specifically, this unprecedented and versatile synthesis strategy can be used to encapsulate essentially any silica-based, carbon-based, metal, metal oxide, or other possible NPs. Noteworthy is that most of the yolk-shell mesoporous silica (mSiO₂) NPs are prepared for the first time. To demonstrate the major structural and compositional advantages of the designed yolk-shell NPs, their applications in the fields of ultralow-dielectric constant (k) materials, drug delivery systems, and catalysts were explored. In detail, the lowest k value of the prepared yolk-shellordered mesoporous silica@mSiO₂/fluorinated polybenzoxazole composite films is 2.02; The obtained yolk-shell mSiO₂/C@mSiO₂/C NPs possess high hydrophilicity and pH-responsive sensitivity; The conversion of the catalytic reaction of the designed magnetic yolk-shell hollow Fe₃O₄@SiO₂/Au@mSiO₂ NPs at 20 min is 97% with a high conversion rate (92%) and recyclability even after 10 reuses. This innovative work lays a solid foundation for freely tailorable yolk-shell encapsulation and will greatly stimulate more efforts devoted to relevant research and development.     

Ni的掺入对复合氧化物LaFeO3的结构及性质的影响

合成子Ｎｉ替代铁酸稀土复合氧化物ＬａＦ３１－ｘＮｉｘＯ３（ｘ＝０．１－０．６），对样品进行了ＸＲＤ、ＩＲ及Ｍｏｓｓｂａｕｅｒ谱测试，结果表明：ｘ＝０＼１，０＼２，０＼３的样品为正交相，ｘ＝０．５，０．６的样品为菱方相；伴随相结构从正交向菱方结构的转变，ＩＲ谱上Ｆｅ（Ｎｉ）－Ｏ键伸振动谱带向高频移动近２０ｃｍ＾－１，Ｍｏｓｓｂａｕｅｒ谱测试表明Ｆｅ均处于＋３自旋态，Ｎｉ离子以＋３价进入晶格。     

基于PMU的电力系统监控体系结构优化设计

文中提出了一种利用有限数量的相量测量单元(PMU)和相量数据集中器(PDC)设计最优监控结构的方法.通过在大量的设定值场景下,使电力系统可观测性曲线的期望值最大化,同时使通信基础设施成本最小化,最终确定PMU和PDC的最佳位置.提出了一种非线性动态扩展卡尔曼滤波(EFK)状态观测器.这种状态观测器可以将暂态行为转换为由...     

圆锥扫描体制雷达跟踪旋转目标的方法研究

针对圆锥扫描体制雷达对目标精密跟踪及测角时由于导弹目标自旋而引起的跟踪失控问题,提出了一种采用窄带FIR滤波器滤除自旋调制信号,提取锥扫信号的解决方法。FIR滤波器具有线性相位,但需要采用高阶滤波才能达到很好的带通特性。该方法经过计算机仿真产生高阶FIR滤波器系数,经过了仿真验证,并在导弹目标跟踪应用中取得了很好的效果。     

Machine learning-based real-time visible fatigue crack growth detection

Many large-scale and complex structural components are applied in the aeronautics and automobile industries.However,the repeated alternating or cyclic loads in ...     

含吸收型色散介质的光子晶体的腔极化激元研究

对色散介质层采用洛仑兹振子模型,通过考虑色散介质层两边的边界条件,可以严格得到表征色散介质层的转移矩阵.通过改变介质层的不同参数,详细研究了含吸收型色散介质的对称光子晶体的腔极化激元.研究发现吸收型色散微腔和增益型色散微腔在简正模耦合,无定型展宽效应和失谐效应方面都可以表现出大致相似的性质,但其在透射强度和耦合模频率飘移方面都有着明显的不同.最后对同时含有吸收型色散介质层和Kerr非线性层的一维对称光子晶体的光双稳行为进行了研究,发现其形成双稳态所需的阈值入射光强比仅含Kerr非线性层的阈值入射光强有所降低.     

多功能雷达脉冲列的语义编码与模型重建

从电子侦察数据中反演多功能雷达的工作模式,是电子侦察领域广泛关注的难点问题,也是充分挖掘电磁大数据情报效益的重要内容,对雷达型号识别、工作状态识别、行为意图推断、精确电子干扰等应用具有直接的支撑作用.该文以多功能雷达信号模型的简洁性为基本依据,参考信息理论定义了雷达脉冲列的复杂度度量规则,并遵循复杂度最小化准则对多功能...     

基于VR技术的智能变电站混合巡检培训系统设计

为提升变电站混合巡检培训系统对学员的培训效率、增加学员的体验感和学习兴趣,设计了一种基于VR技术的智能变电站混合巡检培训系统,通过SolidWorks和3D Max结合设备电气特点、动作特点以及物理特点共同构建变电站设备场景,采用3D Max软件创建三维虚拟变电站场景,便于学员在三维场景中漫游巡检.在实验中,通过变压器...     

Steam-assisted crystallization of highly dispersed nanosized hierarchical zeolites from solid raw materials and their catalytic performance in lactide production

A solvent-free route based on solid raw materials affords higher product yield and lower waste production compared to the traditional hydrothermal synthesis. However, the as-made zeolites usually present blocky aggregation states, limiting their mass transfer and exposure of active sites in catalytic applications. Herein, highly dispersed nanosized hierarchical Beta zeolites with varied Si/Al ratios were prepared via steam-assisted crystallization from ball-milled solid raw materials. Thanks to the sufficient mixing of solid raw materials and favorable migration of solid mixture, nanosized Beta zeolites are obtained that are assembled from nanoparticles (∼15 nm) and possess abundant interconnected intraparticle mesopores. The strategy can also be extended to synthesize nanosized hierarchical ZSM-5 zeolites. The as-prepared Beta zeolite (Si/Al = 10) exhibits outstanding catalytic performance in conversion of lactic acid to lactide (as high as 77.5% in yield). This work provides avenues for simple and cost-efficient synthesis of highly dispersed nanosized hierarchical zeolites, promising their important catalytic applications.

A cost-effective synthesis strategy based on steam-assisted crystallization from ball-milled solid raw materials is developed to prepare a highly dispersed nanosized hierarchical Beta zeolite for conversion of lactic acid (LA) to lactide (LT).