A strontium-free and iron-based oxygen electrode for solid-oxide electrochemical cells (SOCs)

A solid-oxide electrochemical cell (SOC) that converts fuel to electricity back and forth is a possible large-scale storage technique for the renewable energy. Mixed ion-and-electron-conducting (MIEC) perovskites with Sr²⁺ as aliovalent dopants are proposed as the oxygen electrode to alleviate the degradation as in the conventional Sr-doped LaMnO₃. However, the high mobility of Sr²⁺ cation under an electric current, poor chemical compatibility with the yttria-stabilized zirconia (YSZ) of the MIEC perovskites could lead to the loss of long-term performance of the cell stacks. In this study, a novel Sr-free MgO-doped LaFeO₃ (La_0.95Fe_0.7Mg_0.3O_3-δ) showing an acceptable chemical compatibility with YSZ and high stability under anodic/cathodic current is proposed as the oxygen electrode for an SOC. A polarization resistance of 1.75 Ωcm² at 700 °C was observed for the single-phase electrode and the value could be decreased to 0.75 Ωcm² if a nanostructured composite electrode with YSZ was prepared using an infiltration technique.     

Permittivity of ice at radio frequencies: Part I. Coaxial transmission line cell

At radio-frequencies, measurements of the permittivity of ice are sparse and with unknown or large uncertainty. Coaxial transmission lines have been established for frequency-dependent permittivity determination for a broad variety of materials. Here we present a coaxial transmission line setup originally designed for soil samples, now adapted for measuring ice samples between 10 MHz and 1.5 GHz. Measured scattering parameters are assessed for artifacts against a forward calculation based on transmission line theory. A Debye-type relaxation function for the complex permittivity is assumed to obtain the permittivity of ice from the measured full set of four scattering parameters by means of a genetic optimization algorithm. The algorithm is successfully validated against quasi-analytical and iterative computation techniques with reference measurements of a low-loss Teflon standard. Based on the forward calculation and the Teflon standard, the total uncertainty for measuring the real part of the permittivity is estimated to be around 1%. Additional measurements of reference materials air, water, ethanol and methanol are used for validation. The real part of the permittivity of eight artificial pure ice samples is found frequency-independent between 10 MHz and 1.5 GHz at − 20 °C, with a mean value of 3.18 ± 0.01.     

减(定)径机轧辊机架有限元分析及优化设计

利用Pro/MECHANICA软件,分析了减(定)径机重要部件--轧辊机架在最大轧制力下的应力、变形情况,并根据所得结果,利用灵敏度分析方法对机架进行了优化.通过模拟装配以及对优化前后机架的各项性能指标的比较,验证了优化的合理性和有效性.     

Binary nickel ferrite oxide (NiFe2O4) nanoparticles coated on reduced graphene oxide as stable and high-performance asymmetric supercapacitor electrode material

Transition metal oxides are nowadays one of the most important materials in the manufacture of capacitive electrodes. The most important problems with these materials for applied energy storage devices are low specific energy and poor electrical conductivity. In this research nickel ferrite nanoparticles (NiFe₂O₄) and also hybrid of NiFe₂O₄/rGO are synthesized by hydrothermal method and characterized by XRD, Raman, and XPS analysis. The amount of porosity and specific surface area is studied by BET analysis as and surface morphology is studied by SEM and TEM. To investigate the effect of adding rGO to NiFe₂O₄ nanoparticles, from a hybrid electrode superconducting electrochemical tests are performed, including CV, EIS, and charge-discharge. This electrode with a capacitance of 584.63 F/g and capacitance retention of 91% after 2000 consecutive cycles can be a tempting option for supercapacitor applications.     

精分EEG脑网络同步稳定性研究

为了深入表征和刻画精神分裂症患者大脑活动时各个电极通道的状态变化，通过利用复杂网络同步稳定理论以及精分工作记忆实验范式对EEG信号进行分析。从复杂网络角度出发构建脑功能网络，并利用特征谱比值法分析脑网络及其同步性随时间的演化过程。对比实验表明精分患者和正常对照组同步能力具有很大差异且差异主要源于对应脑网络的一个局部化区域S的不同，并通过设计对比实验进一步验证此区域对脑网络同步影响的有效性。脑网络同步稳定区域S的发现对研究神经精神性疾病下脑网络的演化过程提供了新的思路。     

基于多层次模板的脑功能网络特征选择及分类

基于单一脑图谱模板的功能连接网络中提取的特征表示不足以揭示患者组和正常对照组（NC）之间的复杂拓扑结构差异，而传统的基于多模板的功能脑网络定义多采用独立模板，缺乏模板间的关联，从而忽略了各模板构建的功能脑网络中潜在的拓扑关联信息。针对上述问题，提出了一种多层次脑图谱模板和一种使用关系诱导稀疏（RIS）特征选择模型的方法。首先定义了具有关联的多层次脑图谱模板，挖掘模板之间潜在关系和表征组间网络结构差异；然后用RIS特征选择模型进行参数优化，进而提取组间差异特征；最后利用支持向量机（SVM）方法构建分类模型，并应用于抑郁症患者的诊断。在山西大学第一医院抑郁症临床诊断数据库上的实验结果显示，基于多层次模板的功能脑网络通过使用具有RIS特征的选择方法取得了91.7%的分类准确率，相比传统多模板方法的准确率提高了3个百分点。     

Long-term corrosion of cast irons and steel in marine and atmospheric environments

Long-term corrosion trends are important for assessing the remaining life of critical infrastructure. Herein the available literature data for grey cast iron and cast steel exposed to marine and to some atmospheric environments are shown to be consistent with the bi-modal model previously developed for steels. However, the development of the second mode takes longer. This is proposed as resulting from the graphitized zone slowing the diffusion of species controlling the longer term corrosion processes. A practical simplified model and its parameters are proposed.     

安装角度对交叉孔试件振动抛磨效果的影响分析

为探究试件安装角度对交叉孔转接部位抛磨效果的影响,基于离散单元法对交叉孔试件振动抛磨加工工艺进行仿真分析。研究发现：与安装角度为0°,90°时相比,安装角度为45°时,交叉孔转接部位的加工均匀性较好,且转接部位磨损深度的最小值大于安装角度为0°,90°时磨损深度的最小值。基于单因素试验方法,采用ZLC100卧式振动抛磨设备对不同安装角度的交叉孔试件进行抛磨加工试验。结果表明：与安装角度为0°,90°时相比,安装角度为45°时,交叉孔转接部位毛刺的去除效果较好,转接部位倒圆角效果较明显,测得转接部位圆角半径在0.3～0.7 mm范围内,大孔和小孔内侧表面8个区域表面粗糙度归一化值R_a^*有明显的下降趋势,试验得到的结论与仿真分析的结论相符合。     

青黛散外用凝胶对特异性皮炎小鼠的改善作用研究

目的：研究青黛散凝胶（Qingdaipowder Gel, QDPG）对小鼠特异性皮炎（AD）模型的影响及青黛散醇提物的抑菌作用。方法：采用2,4-二硝基氯苯（DNCB）反复皮肤诱导建立小鼠AD模型,将56只小鼠随机分为空白组、模型组、尤卓尔组（Hyd,1.5 mg/cm2）、基质组、青黛散凝胶高剂量组（QDPG-H,240 mg/cm2）、青黛散凝胶中剂量组（QDPG-M,120 mg/cm2）、青黛散凝胶低剂量组（QDPG-L,60 mg/cm2）剂量组。外用皮肤给药,每日1次,连续12 d,分析各组小鼠皮损、耳廓肿胀度、胸腺脾脏指数,苏木素-伊红（HE）染色观察皮损组织的病理变化,酶联免疫吸附测定法（ELISA）检测血清中免疫球蛋白E（IgE）、白细胞介素6（IL-6）、白细胞介素4（IL-4）、肿瘤坏死因子α（TNF-α）和γ干扰素（IFN-γ）的炎症因子水平。采用滤纸片法和最小抑菌浓度（MIC）法,确定青黛散醇提物对特异性皮炎主要致病菌金黄色葡萄球菌、大肠埃希氏菌的抑菌活性。结果：与模型组相比,Hyd组和QDPG各剂量组耳廓肿胀度显著降低（P<0.01）、皮层厚度显著降低（P<0.01）,血清中IL-4、IL-6、IgE、IFN-γ和TNF-α水平显著降低（P<0.01）,IFN-γ/IL-4的比值升高（P<0.05）,QDPG-H剂量组胸腺脾脏指数降低（P<0.05）。青黛散醇提物对大肠埃希氏菌和金黄色葡萄球菌的MIC值分别为31.25 mg/mL和62.5 mg/mL。 结论：QDPG能有效缓解特异性皮炎的症状,其作用机制可通过抑制致病菌、调节T辅助细胞TH1/TH2的平衡,改善AD模型小鼠的皮损。     

红砂岩集料对水稳基层强度与抗软化性能的影响

红砂岩具有遇水软化的特性,通过与石灰岩集料对比,研究了红砂岩粗、细集料硬度与抗软化性能及其对水泥稳定基层(水稳基层)强度与抗软化性能的影响规律,并通过界限含水率、XRD与SEM测试,对比了红砂岩、石灰岩集料浸水前后的矿物成分与微观形貌。结果表明,红砂岩集料浸水后质量减少,硬度降低,抗软化性变差,制备的红砂岩水稳基层强度、软化系数低于石灰岩水稳基层,但红砂岩粗集料制备的水稳基层强度、软化系数降低幅度小于红砂岩细集料制备的水稳基层。红砂岩集料中的黏土矿物遇水崩解剥落、膨胀疏松化是红砂岩水稳基层强度、软化系数降低的主要原因。本研究可以为红砂岩在路面基层材料中的组成设计与工程应用提供理论参考。