Characterization and performance of cobalt-free perovskite-type La0.6Ba0.4Fe0.8Ni0.2O3 − δ cathode material for intermediate-temperature solid oxide fuel cells

Ionics - A novel cobalt-free perovskite La0.6Ba0.4Fe0.8Ni0.2O3 − δ (LBFN) powder was synthesized using a combustion method. The phase composition, electrical conductivity, thermal...     

A novel imaging tool for hepatic portal system using phase contrast technique with hydrogen peroxide‐generated O2 gas

The objective of this study was to investigate the potential of hydrogen peroxide‐generated oxygen gas‐based phase contrast imaging (PCI) for visualizing mouse hepatic portal veins. The O₂ gas was made from the reaction between H₂O₂ and catalase. The gas production was imaged by PCI in real time. The H₂O₂ was injected into the enteric cavity of the lower sigmoid colon to produce O₂ in the submucosal venous plexus. The generated O₂ gas could be finally drained into hepatic portal veins. Absorption contrast imaging (ACI) and PCI of O₂‐filled portal veins were performed and compared. PCI offers high resolution and real‐time visualization of the O₂ gas production. Compared with O₂‐based ACI, O₂‐based PCI significantly enhanced the revealing of the portal vein in vivo. It is concluded that O₂‐based PCI is a novel and promising imaging modality for future studies of portal venous disorders in mice models.     

基于双移位器的FLEXIO模拟SPI总线的设计与实现

针对嵌入式系统设计中专用的串行外设接口SPI数量不能满足要求的问题,提出一种基于双移位器的FlexIO来模拟SPI通信总线的全新方案,首先阐述了FlexIO的硬件架构,然后在分析标准SPI通信协议的基础上,通过对其内部定时器,移位器与芯片引脚的合理配置并结合少量的软件编程设计,最终模拟出拥有全双工,同步功能的SPI通信总线。通过与标准SPI从机通信的实验,表明了用FlexIO模拟的SPI通信总线具有硬件配置灵活,软件需求少且通信可靠的优点,同时也对用它来模拟其他类型的串行通信总线提供了一定的参考价值。     

高温高压下Zr2AlC的结构及热学性质的第一性原理

利用密度泛函理论研究了高温高压下Zr₂AlC的结构和热力学性质,计算得到Zr₂AlC的晶格参数与实验值符合较好．研究了Zr₂AlC的弹性常数、体模量、剪切模量和杨氏模量等力学性质随压力变化的趋势．同时研究了维氏硬度随压力的变化趋势．通过计算得到的杨氏模量预测了Zr₂AlC的弹性各向异性．最后,基于准简谐德拜模型,成功预测了Zr₂AlC的德拜温度、热容、热膨胀系数和Grüneisen参数随着压强和温度的变化关系.     

飞秒激光冲击AZ31B镁合金过程的数值模拟

采用有限元分析法对飞秒激光冲击AZ31B镁合金进行数值模拟,研究了激光冲击处理对镁合金变形过程的影响,分析了单脉冲激光冲击下材料内部的位移、动能、应力和应变的分布情况,得到了材料的瞬态速度和应变率变化过程.仿真结果表明,单脉冲飞秒激光冲击镁合金产生的塑性变形,可在材料表面形成微米级凹坑,中心点处最大位移为34μm,最大变形速度390m/s;在冲击初期,材料表面的应力和应变主要分布在冲击区域中心节点和边缘附近,并且得到镁合金的最大应力和最大应变率分别为955 MPa和1.8×106 s-1.研究结果能够为深入分析飞秒激光与镁合金作用时材料变形参量的变化规律提供数值理论依据.     

铜铟铝硒硫薄膜的低成本非真空混合法制备

采用溶剂热法制备出铜铟铝硒Cu(In,Al)Se₂ (CIASe)粉末,然后滴涂铜铟铝硒CIASe浆料获得前驱体薄膜,最后通过硒化/硫化过程制备出铜铟铝硒CIASe和铜铟铝硒硫CIASeS薄膜．通过XRD、SEM、XRF及光吸收等表征,发现所制备的薄膜为单相的黄铜矿结构,具有(112)择优取向．同时,在使用硫元素替代硒之后,薄膜的XRD主峰向高的2θ角度漂移,多孔薄膜也变得更加致密．薄膜带隙值也增加到更为合适的范围,从1.21 eV增加到1.33 eV,这也说明了硫化过程有利于提高CIASeS薄膜的质量．     

Decoupled two‐grid finite element method for the time‐dependent natural convection problem I: Spatial discretization

In this article, a decoupled two grid finite element method (FEM) is proposed and analyzed for the nonsteady natural convection problem using the coarse grid numerical solutions to decouple the nonlinear coupled terms, and the corresponding optimal error estimates are derived. Compared with the standard Galerkin FEM and the usual two‐grid FEM, our algorithm not only keeps good accuracy but also saves a lot of computational cost. Some numerical examples are provided to verify the performances of the decoupled two‐grid FEM. Both theoretical analysis and numerical experiments show the efficiency and effectiveness of the decoupled two‐grid FEM for the nonsteady natural convection problem. © 2015 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 2135–2168, 2015     

Improvement of resistive switching fluctuations by using one step lift‐off process

Bipolar resistive switching characteristics are investigated in ZrO₂ containing Cu thin layer devices, particularly for the self‐isolated‐structure device fabricated by one step lift‐off process. Compared with the traditional‐structure device, the self‐isolated‐structure device shows more uniform resistive switching characteristics. This is because the isolation of each device cell has negligible influence on each other and thus mitigates possible crosstalk between each cell. These results suggest that the feasibility of good stabilization of the resistive switching parameters can be obtained through one step lift‐off process. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Distributed Bragg reflector laser(1.8 μm) with 10 nm wavelength tuning range

We report a 1.8 μm two-section distributed Bragg reflector laser using butt-jointed In Ga As P bulk material as the waveguide core layer. The threshold current is 17 m A and the output power is 8 m W on average. The threshold current, output power, and emitting wavelength dependences on temperature are measured. The obtained wavelength tuning range is 10 nm. This device has potential applications in simultaneous multiple-gas detection.