Control of barium ferrite decomposition during spark plasma sintering: Towards nanostructured samples with anisotropic magnetic properties

The sintering of barium ferrite (BaM) nano-sized powders by spark plasma sintering was studied. At the surface of the samples, an iron-rich layer (magnetite) was formed due to the decomposition of BaM and segregation in the secondary phases. To prevent the formation of secondary phases different protection layers between the graphite mould and the sample were used. Their effect on the sample microstructure was studied by X-ray diffraction and scanning electron microscopy. The most suitable protection layer was a highly dense sintered disc of aluminium oxide. Using this dense protection layer, sintered discs of BaM with 82% of theoretical density and grains of 90 ± 50 nm were obtained. A magnetic anisotropy was achieved from the sintering of the BaM particles with the largest shape anisotropy.     

Impact of oxygen concentration during the deposition of window layers on lowering the metastability effects in Cu(In,Ga)Se2/CBD Zn(S,O) based solar cell

The purpose of the present paper is to focus on the impact of oxygen gas partial pressure during the sputtering of i‐ZnO and ZnMgO on the transient behavior of Cu(In,Ga)Se₂ (CIGSe) based solar cells parameters when a CBD‐Zn(S,O) buffer layer is used. Based on electrical characterization of cells, it is observed that the effect of light soaking is different on J–V characteristics depending on whether oxygen is or is not present during the first deposition time of the i‐ZnO or ZnMgO layers. In fact, when cells are prepared with standard i‐ZnO, the efficiencies are very low and a pronounced transient behavior is observed. However, when the first 10 nm of i‐ZnO or ZnMgO is formed by sputtered layer without adding oxygen during the process, depending on the thickness of the buffer layer, the transient effects strongly decreases. It is then possible to get stable cells reaching efficiencies quite similar to the CdS reference cells, especially with ZnMgO, without any post‐treatments. Copyright © 2015 John Wiley & Sons, Ltd.     

面向教育领域的基于SVR-BiGRU-CRF中文命名实体识别方法

在教育领域中,命名实体识别在机器自动提问和智能问答等相关任务中都有应用。传统的中文命名实体识别模型需要改变网络结构来融入字和词信息,增加了网络结构的复杂度。另一方面,教育领域中的数据对实体边界的识别要十分精确,传统方法未能融入位置信息,对实体边界的识别能力较差。针对以上的问题,该文使用改进的向量表示层,在向量表示层中融合字、词和位置信息,能够更好地界定实体边界和提高实体识别的准确率,使用BiGRU和CRF分别作为模型的序列建模层和标注层进行中文命名实体识别。该文在Resume数据集和教育数据集(Edu)上进行了实验,F₁值分别为95.20%和95.08%。实验结果表明,该文方法对比基线模型提升了模型的训练速度和实体识别的准确性。     

超高速滑动电接触CuCrZr合金轨道表面磨损机制及电接触性能

电磁轨道发射具有典型超高速滑动电接触特性（出口速度大于等于2 000 m/s）,电磁轨道表面会发生磨损。为研究轨道表面磨损状态与接触电阻之间关系,通过开展电磁轨道发射试验,研究发射后的CuCrZr轨道表面沉积层的形成与磨损机制,揭示枢轨间静态接触电阻的演变规律,总结沉积层的形成与接触电阻的关联关系。结果表明：沿着发射方向,轨道表面沉积层覆盖面积逐渐增大,沉积层的形成机制由摩擦材料转移变为电枢表面熔化飞溅,表面磨损特征由机械磨损向电气磨损转变;由于轨道不同位置沉积层形成原因不同,导致表面粗糙度分布不一致,枢轨间静态接触电阻随接触沉积层形貌特征改变呈现上升、下降及波动3个变化阶段;并且枢轨间静态接触电阻随着接触压力的增大而减小。研究成果对电磁轨道发射装备的研究及发射动力学研究具有理论价值。     

烟煤水煤气气化炉运行的可行性分析

烟煤水煤气气化炉是将双火层煤气发生炉的气化原理用于水煤气气化的一种炉型。介绍了双火层气化炉的炉型规格、供气形式和半水煤气组成;从煤气中CO2和CH4含量、气化炉反应温度、蒸汽量的调整等方面分析了烟煤水煤气气化炉生产运行的可行性;介绍了烟煤水煤气气化炉的结构形式和工艺流程;计算了原料煤成本的经济效益,结果表明,4万t/a合成氨装置每年可节约原料煤费用1160万元,20万t/a甲醇装置每年可节约原料煤费用6960万元。     

Modification of TiAlV Alloys with Hybrid Layers Containing Metallic Nanoparticles Obtained by the Sol–Gel Method: Surface and Structural Properties

The aim of the work was to obtain hybrid coatings containing silver, copper, and zinc nanoparticles on the TiAlV medical alloy via a sol–gel process. The developed layers were designed to bring about a bactericidal and fungicidal effect, as well as for protection against surgical scratches during the implantation of implants used in veterinary medicine. In this work, the authors focused on evaluating the microstructure (SEM + EDS); the structure (XRD, FTIR); and the surface properties, such as wettability, free surface energy, and roughness of layers with various concentrations of metallic nanoparticles (2 and 5 mol %). Our results confirmed that the sol–gel method enables the easy manufacturing of hybrid layers endowed with different porosity values as well as various shapes and sizes of metallic nanoparticles. A higher concentration of nanoparticles was observed on the surface containing 5 mol % of metallic salts. The highest degree of homogeneity was obtained for the layers containing silver nanoparticles. In addition, the silver nanoparticles were round and had the smallest dimensions, even below 20 nm. The FTIR and XRD structural studies confirmed the presence of an organosilicon matrix containing all three types of the metallic particles. We conclude that the higher concentration of nanoparticles influenced the alloy surface parameters.     

准噶尔盆地柴窝堡区块储层油气识别与应用

在研究了以岩心、录井及实验室分析资料的基础上,采用了岩心刻度测井分析技术,建立了岩性判别标准和储层物性及含油气性测井解释模型,结合测试成果资料,制定了油气层判别标准,并对柴窝堡地区储层物性及含油气性进行了评价。     

非均匀演化算法及其应用

提出一种基于非均匀变异的演化算法模型;基于随机过程理论分析了该算法的自适应性,用该算法求解了实际的“油层结垢”问题;基于随机优化领域经典的高维多峰测试函数,同已有的同类算法做了对比.实验结果表明：在没有引入任何额外参数和计算的前提下,该算法具有更好的收敛性和稳定性.     

客车涂装底层材料配套性分析

针对南方客户在使用我司客车一段时间后,车身涂层不同程度出现了起泡的质量问题,进行了现场查看,发现起泡位置在车身左右侧蒙皮,且发生在涂层最底层。初步分析原因是热镀锌板+阴极电泳漆 +原子灰三者之间配套存在问题,通过热镀锌板 +阴极电泳漆 +原子灰三者之间的耐高温 80 ℃配套试验,以及室外曝晒试验,得出镀锌板表面是否钝化、电泳漆膜致密程度和原子灰苯乙烯含量是造成涂层底层起泡的主要原因。为了控制涂层起泡问题,重新修订了我司原子灰、镀锌板、电泳漆的技术标准以及部分工艺文件。     

Double layers glaze analysis of the Fujian export blue-and-white porcelain from the Witte Leeuw shipwreck (1613)

Witte Leeuw was a cargo ship owned and operated by the Dutch East Indian Company. The wreck of this vessel is known for yielding a comprehensive range of Jingdezhen manufactured, blue-and-white export porcelains, particularly kraak wares; together with Fujian blue-and-white export porcelains, known as Swatow wares. A large number of ceramic fragments have been recovered from this wreck and currently reside in collections at the Rijksmuseum. For this study nine ceramic specimens were selected for further investigation, with the aim of determining the structure, composition and manufacturing process of the double-layer glazes. Both digital optical microscopy and scanning electron microscopy were used to examine the glaze morphology and microstructure; whilst energy dispersive x-ray spectroscopy was utilised to measure the spatial distribution of chemical elements and to determine bulk elemental compositions. Raman spectroscopy was also trialled, with the technique being applied to the measurement of molecular vibrations within the silicon-oxygen network and associated alkali metal oxides, with the aim of identifying potential differences in the glaze layers. Examining the ceramic specimens, the blue decorations were applied between two layers of glaze, and the majority of the blue colour extends into the outermost layer, often exhibiting dissolution in the outer layer glaze. The two layers of the glaze appear to be formulated from different compositional recipes. Some export Swatow blue-and-white wares made in the Wanli Period (1573–1620) were glazed twice and fired twice.