CeO_2基极限电流氧传感器的研究

采用Gd掺杂的CeO2(Ce0.8Gd0.2O1.9,CGO)粉体,干压成型后于空气气氛下1450℃烧结4 h。通过物理特性分析,发现在该烧结制度下烧结成型的样品基本满足氧传感器对敏感材料的要求。制备了一种新型结构的致密扩散障型极限电流氧传感器。经测试,发现该传感器在较高氧体积分数范围内有较好的极限电流特性,并为此建立了相关的理论模型,较好地解释了此类传感器极限电流和氧体积分数的关系。     

项约束先过滤的最大频繁项集挖掘算法

在稠密型数据库中,现有最大频繁项集挖掘算法效率低、耗时长,挖掘结果模糊,不利于用户使用。为此,提出一种项约束先过滤的最大频繁项集挖掘算法——VCM。利用项包含约束过滤数据库,使用垂直数据表示数据集,采用深度优先的挖掘策略对数据库进行最大频繁相集的挖掘。实验结果表明,该算法快速有效,尤其在挖掘具有长模式的稠密数据库时优势明显。     

反应性化学品泄漏扩散的三维数值模拟

多晶硅副产物四氯化硅泄漏后形成重气云,易与水蒸气发生反应,生成四氯化硅、氯化氢和硅酸的混合有毒气云,威胁人类安全,导致严重的生态和环境危害。针对四氯化硅泄漏后形成的重气云的三维大气扩散与反应迁移过程建立了传递转化模型并采用计算流体力学(CFD)进行模拟研究,化学反应模型采用漩涡破碎模型(Eddy-Break-UpModel)。模拟研究了四氯化硅气体与水蒸气反应过程中四氯化硅、氯化氢、硅酸等有毒物质的空间分布与迁移转化情形。四氯化硅受重力作用下沉并向周围扩展,迎风面处的四氯化硅下沉触碰到地面后向上风侧移动,但主体向下风向迁移;生成的毒害性氯化氢覆盖范围较四氯化硅广泛;反应物和生成物在近地面的浓度较大,威胁环境安全;水解反应消耗水分导致脱水效应和反应放热升温,会对该区域生态造成严重危害。研究结果为反应性化学品事故处理提供了依据。     

钙钛矿型致密膜透氧过程的应用研究

对钙钛矿型致密膜的透氧过程进行了实验研究,验证了所建数学模型的正确性,并对数学模型中的材料参数、应用范围、模型对厚度的敏感性及模型在极限条件下的适用性等进行了分析研究,力图实现以模型为手段,优化实验操作条件,用模型来预测不同工艺条件对膜透氧速率的影响,减少探索性实验的工作量,进而为实现其工业化应用提供指导。     

利用在轨航天器扰动响应辨识其动力学参数的研究

从结构模态参数的可识别性出发,结合时域频域参数识别技术和数字处理技术,开发出航天器动力学特征参数在轨辨识系统,系统包括硬件和软件。在此基础上设计了模拟在轨航天器的试验验证系统,以检验辨识算法和设计软件的可靠性以及航天器在轨辨识的实时性,该试验系统包括一个对称的双梁结构,利用对称结构的弱耦合可得到多个密集模态。试验和模拟数字考核结果表明系统辨识算法可靠,精度可以到达设计要求。     

正压浓相气力除灰系统出现的问题及解决措施

介绍了安庆石化热电厂正压浓相气力除灰系统。探讨了影响气力除灰的因素。分析了该系统在运行中出现的堵管、磨损及输灰时间过长等问题的原因,并提出了相应的解决措施。     

浅谈超浓相输送技术在85kA预焙槽的节能应用

1999年该电解铝厂引进超浓相输送技术并进行了10台电解槽工业实验，经过工业实验，确认超浓相输送技术在85kA预焙槽上应用的可行性之后，2001年完成技术改造后将此技术大规模应用于260台三个系列85kA纵向排列中间点式下料电解槽，经一年多的吸收和改进，已成功实现了这一世界先进技术在85kA纵向排列电解槽的平稳运行，不仅比原来的罐车加料方式成本更低，而且填补了超浓相输送技术在中小型预焙铝电解槽上应用的空白。     

Impact of precursor preparation on density of gadolinium iron garnets synthesized via reactive sintering

Gadolinium iron garnet was obtained from two different precursors, homogenized in isopropyl alcohol and in an aqueous environment with a fixed pH. In the first case, it was a mixture of goethite (FeO(OH)) and gadolinium oxide (Gd₂O₃); in the second, a mixture of GdIP (GdFeO₃) and α-Fe₂O₃. Conditions of homogenization in the aqueous environment were selected based on the zeta (ξ) potential measurements as the function of pH. DSC measurements of the output powder mixtures allowed the identification of the effects observed during the temperature rise. In the case of the material obtained from a mixture of goethite (FeO(OH)) and gadolinium oxide, with the increasing temperature, we observe three effects, the first of which corresponds to the phase transformation of goethite into α-Fe₂O₃, the second corresponds to the reaction of gadolinium iron perovskite (GdIP) formation, and the third to the reaction in which a gadolinium iron garnet (GdIG) is formed. However, in the case of heat treatment of the mixture of GdIP and α-Fe₂O₃, we only observe the effect responsible for a solid state reaction leading to the formation of gadolinium iron garnet. Dilatometric measurements allowed to determine the changes in linear dimensions at various stages of reaction sintering. The resulting materials were sintered at temperatures of 1200, 1300, and 1400 °C. In the case of the material obtained from a mixture of perovskite and iron (III) oxide, already at the temperature of 1300 °C, a density has been obtained at around 95% of the theoretical density, and the temperature of 1400 °C allowed achieving a density of 97% of the theoretical density. Whereas, for the material obtained from a mixture of goethite (FeO(OH)) and gadolinium oxide, a density above 95% of theoretical density was achieved only at 1400 °C.     

Enhanced densification of thin tape cast Ceria-Gadolinium Oxide (CGO) layers by rheological optimization of slurries

Optimized CGO-based slurries are formulated and shaped into thin dense layers via a tape-casting process. The formulation is adjusted with respect to the rheological behaviour. The internal structure and flow properties of slurries are explored with the aim of identifying the required conditions to obtain thin dense CGO layers at reduced sintering temperatures (1200 °C). We demonstrate a correlation between the rheological properties of the slurries, the sintering behaviour and the microstructure of the resulting tapes. Remarkably, a dense CGO layer less than 20 µm thick is obtained with a non-congested slurry, having optimized ceramic loading and liquid-like behaviour.