Nanostructured GDC-impregnated La0.7Ca0.3CrO3−δ symmetrical electrodes for solid oxide fuel cells operating on hydrogen and city gas

Nanostructured Gd_0.1Ce_0.9O_1.95 (GDC)-impregnated La_0.7Ca_0.3CrO_3−δ (LCC) composites were investigated as symmetrical electrodes for La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ (LSGM)-supported solid oxide fuel cells (SOFCs) without using interlayer at anode/electrolyte interface. The impregnation of aqueous Gd_0.1Ce_0.9(NO₃)_x solution into the porous LCC electrode backbones was found to form nanosized GDC particles on LCC surfaces after calcining at 850 °C for 30 min. The optimized performance of electrodes for SOFCs had been achieved through the impregnation cycles of 3-7 times. The introduction of the ion conducting phase GDC in nanometer significantly enhanced the symmetrical electrode performance. The symmetrical cell with the impregnation of five times displayed the best performance and the maximum power densities were 521 mW cm⁻² and 638 mW cm⁻² at 850 °C and 900 °C with dry H₂ as fuel, respectively. Using commercial city gas containing H₂S as fuel, the maximum power densities of the cell reached 362 mW cm⁻² and 491 mW cm⁻² at 850 °C and 900 °C, respectively. The microstructure, valence state of Ce element and electrochemical stability of the nanostructured GDC-impregnated LCC composites were also discussed.     

智慧校园网的云计算安全体系架构的探索

随着信息技术在不断的更新,教育信息在不断的发展,计算和虚拟化技术已经逐渐的应用到智慧校园的建设中,该技术的应用提高了数字服务在学校的管理,本文针对云计算以及智慧校园的具体现状进行分析,主要从物理环境、网络、数据以及管理四个方面进行研究,实现了对智慧校园网的构建。     

Superior electrode performance of mesoporous hollow TiO2 microspheres through efficient hierarchical nanostructures

Mesoporous hollow TiO₂ microspheres with controlled size and hierarchical nanostructures are designed from a process employing in suit template-assisted and hydrothermal methods. The results show that the hollow microspheres composed of mesoporous nanospheres possess very stable reversible capacity of 184 mAh g⁻¹ at 0.25C and exhibit extremely high power of 122 mAh g⁻¹ at the high rate of 10C. The superior high-rate and high-capacity performance of the sample is attributed to the efficient hierarchical nanostructures. The hollow structure could shorten the diffusion length for lithium ion in the microspheres. The large mesoporous channels between the mesoporous nanospheres provide an easily-accessed system which facilitates electrolyte transportation and lithium ion diffusion within the electrode materials. The electrolyte, flooding the mesoporous channels, can also lead to a high electrolyte/electrode contact area, facilitating transport of lithium ions across the electrolyte/electrode interface. The small mesopores in the meosporous nanospheres can make the electrolyte and lithium ion further diffuse into the interior of electrode materials and increase electrolyte/electrode contact area. The small nanoparticles can also ensure high reversible capacity.     

热连轧厚控精度分析及提高精度的途径

分析和实践表明，造成热连轧机厚控精度远低于连轧机的主要原因是活套控制系统与厚度控制系统的相互干扰，采取改进活套支持器结构，多变量最优控制和张力与厚度解耦控制等虽然取得了一定效果，但受连轧基本理论－秒流量相等条件的限制，并未取得突破性进步，特别是以流量测厚值为标准，直接影响了自适应的效果，连轧分布参数动态数学模型为解决厚度与张力的干扰提供了新思路，而数学模型与人工智能结合的协调推理网络为其具体实现方     

Multiferroic and magnetoelectric properties of single-phase Bi0.85La0.1Ho0.05FeO3 ceramics

Single-phase Bi_0.85La_0.1Ho_0.05FeO₃ multiferroic ceramics were prepared by a rapid liquid sintering method. The ceramics exhibited an obvious ferroelectric loop with a remnant polarization of 11.2 μC/cm² and also showed weak ferromagnetism with the remnant magnetization of 0.179 emu/g at room temperature. A considerable enhancement of the polarization on magnetic poling and a dielectric anomaly in the vicinity of the antiferromagnetic transition temperature due to the intrinsic magnetoelectric coupling effect were observed in Bi_0.85La_0.1Ho_0.05FeO₃ ceramics. The dielectric constant for the Bi_0.8La_0.1Ho_0.05FeO₃ samples at room temperature decreases with increasing applied magnetic fields, and the coupling coefficient (?′(H) − ?′(0))/?′(0) reaches −1.04% at H = 10 kOe.     

A heuristic block-loading algorithm based on multi-layer search for the container loading problem

This paper presents an efficient heuristic block-loading algorithm based on multi-layer search for the three-dimensional container loading problem. First, a basic heuristic block-loading algorithm is introduced. This algorithm loads one block, determined by a block selecting algorithm, in one packing phase, according to a fixed strategy, until no blocks are available. Second, the concept of composite block is introduced, the difference between traditional block and composite block being that composite block can contain multiple types of boxes in one block under some restrictions. Third, based on the depth-first search algorithm, a multi-layer search algorithm is developed for determining the selected block in each packing phase, and making this result closer to the optimal solution. Computational results on a classic data set show that the proposed algorithm outperforms the best known algorithm in almost all the test data.     

井下地电阻率观测中装置系数的计算——以天水地震台井下观测为例

面对日趋严重的环境干扰问题,我国已有多个地震台开展井下地电阻率观测试验,以减少或消除场地中出现的各种干扰影响,这些观测试验中一般采用较短极距的四极观测装置。在四极地电阻率观测装置中,由于装置系数与电极位置及电流在空间的分布有关,因此井下地电阻率观测的装置系数不能以电极在地表的方式计算,而应针对不同的观测装置情况,以半无限空间、全空间或者不完全全空间的方式计算。本文以甘肃省天水地震台井下地电阻率观测为例,详细说明了各种不同装置情况下装置系数的计算方法,期望能为今后井下地电阻率观测提供有益的帮助。     

过程工业供应链流结构及其管理研究

与离散制造业相比，过程工业具有大批量、连续性、高能耗等特点，根据过程工业的自身特点和复杂性，本文提出了过程工业供应链的概念，分别建立了组成该复杂供应链的物质流、能量流、信息流、资金流、工件流和人件流六大流的动态结构，并以此为基础，通过分析国内外过程工业供应链管理的研究和应用现状，建立了针对复杂过程系统的综合集成的过程工业供应链管理框架。     

Active roles of helium in the growth of hydrogenated microcrystalline silicon germanium thin films

A combination of hydrogen and helium dilutions was introduced when the microcrystalline silicon germanium (μc-SiGe:H) thin films were prepared by very high frequency plasma enhanced chemical vapor deposition on a low-temperature substrate. An optimum helium flow rate was found to achieve the structural uniformity in the growth direction, while Ge content was found to nearly keep constant with varying flow rates of helium. An abundance of atomic H was detected in plasma due to the attendance of helium and no obvious photosensitivity deterioration was observed on the thin film with a high crystalline volume fraction. The active roles of helium were identified by analyzing the mechanism in the plasma, where both metastable He_m^? and He⁺ can accelerate the diffusion of Ge related radicals and passivation of the dangling bonds on the growth surface, respectively. These phenomena have been revealed by experimental results. Therefore, a combination of hydrogen and helium dilutions can improve the structure of the μc-SiGe:H thin films with little degradation of photo-electronic properties.     

CBD现象的启示与高层建筑的近地空间

以城市设计的视角,结合当今流行的“CBD现象”,分析了当前大城市中心区建设与改造过程中暴露出的问题,并指出高层建筑近地空间与城市空间相结合的必要性。希望通过高层建筑近地空间与城市空间的结合,使高层建筑与城市从功能以及环境等各个方面得以整合,达到城市可持续发展的目标。