降水防砂复合材料的研究与应用

针对大港油田疏松砂岩区块含水上升快、出砂加剧,常规防砂工艺技术无法解决既防砂又能有效降水的问题,研制出了一种自身可固结的颗粒型降水防砂复合材料（粒径0.3～0.5,0.5～0.7和0.7～1.4 mm）。采用正交试验进行了材料配方优选,并对优选出的材料进行了固化温度和固化时间对人工岩心固结强度和渗流能力的影响评价、耐酸碱介质性能评价和岩心稳定性评价。结果表明:该系列降水防砂复合材料适用于井温30～80 ℃的油井,人工岩心抗压强度大于3 MPa,液相渗透率0.3～0.8 μm2（根据粒径可以调节）。该降水防砂复合材料在大港油田成功实施了16井次,防砂施工成功率100%,防砂有效率93.8%,平均降水率达14.7%,取得了较好的降水防砂效果。      

燃气能源站主机设备风险及故障分析方法研究

针对目前分布式能源站由于没有相适宜的设备维护管理模式导致运行中存在着诸多问题,提出了采用故障模式及影响分析(FMEA)法,对燃气能源站中主机设备进行风险评估分析,以找出风险较高的主机设备典型缺陷项目。基于此,以"流量仪表指示异常"典型缺陷项目为例,采用故障树分析(FTA)法挖掘缺陷项目的主要影响因素(底事件),以期为燃气能源站主机设备的维护提供新的思路。     

Synthesis of monodisperse CdS nanowires and their photovoltaic applications

Cadmium sulphide (CdS) nanowires with a monodisperse diameter of 3.6 nm and an aspect ratio of 10–170 were successfully synthesized using a simple and reproducible hot coordinating solvents method. The morphology and optical properties of the CdS nanocrystals were investigated using transmission electron microscopy (TEM), high-resolution TEM (HRTEM) ultraviolet–visible (UV–Vis) absorption spectroscopy and photoluminescence (PL) spectroscopy. It was found that using a long alkyl chain phosphonic acid-octadecylphosphonic acid (ODPA) causes a low diffusion rate and low reactivity which help to control the morphology of the nanocrystals. The timing of the injection process was also found to have critical effect on the morphology of the nanocrystals. Sharp peaks in both the UV–Vis absorption and PL spectra indicate that the size distribution of the diameter is nearly monodisperse. The photovoltaic properties of photovoltaic devices made with a blend of our nanowires and poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) were also investigated. Devices made with the nanowires were found to have double the I_sc observed in devices made with lower aspect ratio CdS nanorods. The possible reason of low photocurrent and high V_oc is maybe due to the presence of ligand in the nanocrystals.     

结构扩展的非负矩阵分解社区发现算法

提出结构扩展的非负矩阵分解社区发现算法(nonnegative matrix factorization with structure extension, NMF-SE),通过结构扩展,加强相邻节点结构相似性,提高节点间连接的稠密度,从而提高非负矩阵分解在社区发现中的表现。结构扩展过程使节点将自身结构以一定的比例传递给周围的节点,从而使相邻节点间能够得到对方的拓扑结构信息。该过程构造了新的特征矩阵,使非负矩阵分解(nonnegative matrix factorization, NMF)更好地适用于社区发现,在图正则化的半监督任务中能更好地融合先验信息。在人工网络和真实网络上进行试验验证的结果表明,NMF-SE算法有效提高了复杂网络社区发现的准确性。     

氨基酸作为手性源在有机合成中的应用

综述了近年来以氨基酸为手性源在合成手性生物碱、手性氨基醇、手性氨基醛和手性催化剂等化合物中的研究现状,并对氨基酸作为手性源在有机合成中的应用前景进行了展望。     

应用超声波技术评价氧化膜类缺陷检出率的可行性研究

重点讨论了超声波技术检测铝合金预拉伸板材中氧化膜类缺陷的可行性和检出率,从理论和实际两个方面分析了影响氧化膜缺陷检出率的主要因素,并提出科研性结论。     

Double-Side Si Photoelectrode Enabled by Chemical Passivation for Photoelectrochemical Hydrogen and Oxygen Evolution Reactions

This paper describes a Si photoelectrode with an ultra-long minority carrier diffusion length (1940 µm) passivated by an amorphous Si layer, which provides a chemically passivated surface. With this extremely long carrier diffusion length, it is possible to separate the catalyst layer (metal) with the light absorption region on different sides of the Si photoelectrode, forming a double-side Si photoelectrode for photoelectrochemical water reduction and oxidation. The obtained photocathode exhibits a photocurrent of 39 mA cm⁻² and applied bias photon-to-current efficiencies (ABPE) of 15.4% with stability up to 100 h. Meanwhile, 38.5 mA cm⁻² photocurrent and ABPE of 5.8% with a 200 h stability are achieved when this structure is used as a photoanode. A monolithic unbiased artificial leaf is constructed, yielding an unbiased solar to hydrogen conversion efficiency of 3.7%. This chemically passivated Si photoelectrode breaks the trade-off between carrier transport and surface passivation in conventional Si photoelectrodes.     

基于改进正余弦优化算法的多阈值图像分割

针对多阈值图像分割方法计算量大、分割精度低的问题,提出了基于改进正余弦算法（improved sine cosine algorithm,ISCA）的多阈值图像分割方法。首先对种群进行混沌初始化来提高初始种群质量;其次根据粒子适应度值的大小自适应地调整参数;最后引入反向学习策略并择优选取粒子。伯克利图像和植物冠层图像分割实验的结果表明,该算法的运行时间较短,而且分割精度较高,具有较强的鲁棒性。     

计算机辅助肺功能定量分析系统的开发与设计

在对胸部CT（Computed Tomography）序列图像进行慢性阻塞性等肺疾病诊断时,需要获取相关的肺功能指标来给医生提供参考依据。为此,开发了一个用于肺功能定量分析的计算机辅助系统。系统首先结合多种分割方法实现了三维肺实质的分割,然后采用体绘制技术重建出肺部组织的三维模型,最后利用分割结果实现了对肺功能指标的定量分析。此外,针对医生个性化的需求,该系统还实现了局部肺实质VOI（Volume of Interest）的肺功能定量分析和肺实质任意指定感兴趣CT值范围内的肺功能定量分析。