基于锚节点的无线传感网离群值检测算法

在无线传感网离群值检测算法中,如何自适应调整离群值检测算法的参数是一项重大挑战。由于节点之间存在相关性,不能孤立地去考虑单个传感器节点,因此根据其周围节点情况来动态设置节点参数很有必要。在文中提出一种基于锚节点的无线传感网离群值检测算法,该算法预先为锚节点设置最佳参数,同时计算锚节点与普通节点之间的相关性,利用大小根堆、滑动窗口与标准差来动态地调整每个普通节点的参数,并将其转换为锚节点。最终每个节点都能自适应地将参数调整为最佳。仿真实验表明：在自适应调整方式下,检测算法的真阳性率在84.3%以上,假阳性率在20%以下,并且能够将数据正确地分离出来。     

对二甲苯增产技术发展趋向

综述了国内外芳烃联合装置中甲苯歧化与烷基转移工艺、甲苯择形歧化工艺和重芳烃脱烷基工艺近年来技术进展情况,并分析了各种技术的优势与不足之处。提出了未来增产二甲苯工艺技术发展的趋向,指出甲苯歧化与烷基转移技术今后发展的重点是高空速、低氢烃比、高选择性和加工更多C9+A的催化剂的研究开发;甲苯择形歧化与苯／C9A烷基转移组合工艺具有降低生产成本、增产对二甲苯的技术优势,期待实现工业化;甲苯甲醇甲基化制高浓度对二甲苯技术,随着天然气化工的发展具有良好的应用前景,值得关注。此外还简述了具有前瞻性的对二甲苯合成新技术的研究开发进展。     

Improved gain characteristics of high concentration erbium-doped phosphate fiber amplifier

Both cooperative up-conversion and pair-induced concentration quenching of erbium-doped phosphate fiber with high doping concentration are considered for the first time in this letter. The dependence of the calculated gain on pump power is compared with measured data, and the results show that ion pair may exist in erbium-doped phosphate fiber with doping concentration of 3.8/spl times/10/sup 26/ ion/m/sup 3/. For several erbium-doped phosphate fibers with different lengths, improved gain may be obtained with higher doping concentration.     

确定层状复合材料界面结合强度的新模型

本文提出了一个确定层状复合材料界面结合强度的新模型,即由两种材料交替完全粘结在一起的复合梁。利用材料力学方法对这种梁进行了应力分析,包括正应力分析和剪应力分析。研究了两种情况:一种情况假设两种材料均是线弹性材料;另一种情况假设其中一种材料是纯线弹性材料。而另一种材料是理想弹塑性材料。本文给出的复合梁剪应力的计算公式为复合材料界面剪切强度的测定提供了比较精确的计算公式。     

钢管倒棱机滑座制动失灵原因剖析

通过对倒棱机滑座能耗制动电控原理分析，阐述了造成制动失灵的原因，并对这些原因进行了较深刻的剖析，指出了故障点及处理方法，可为现场技术人员和维修工人提供方便。     

氢对18－8型奥氏体不锈钢焊缝金属力学性能与组织的影响

考察了高压气相热充氢对１８Ｃｒ－８Ｎｉ型奥氏体焊缝金属的力学性能与微观组织的影响。定量测试结果表明，充氢后焊缝金属的塑性明显降低，而强度变化不大；氢抑制了α＇马氏体的生成，由此否定了氢致α＇马氏体转变导致氢脆的观点。     

Synthesis,crystal structures and photoluminescent properties of the complexes of a new coumarin derivative with lanthanide ions

A new coumarin-based podand-type ligand (L) and its five complexes [Ln(NO₃)₃L] (Ln = Pr (1), Eu (2), Gd (3), Tb (4) and Er (5)) were synthesized. The X-ray single-crystal diffraction analyses indicate that these complexes are isomorphous and lanthanide ions are ten-coordinated. The tetradentate ligand forms a half-ring coordination structure with its oxygen atoms and the distances of its two chelate chains vary regularly with the ionic radii. The photoluminescence properties were also investigated by phosphorescence, quantum yields and lifetime.     

东沟尾矿坝渗透系数反演分析

尾矿坝运行中排水能力分析、渗流分析至关重要,直接关系着工程安全和效益以及下游人民生命财产安全。而渗流分析中渗透系数准确性直接关系到渗流分析的准确性。渗透系数有些通过实验获得,但与现场参数有较大的误差。采用三维有限元,使用“反问题正算法”,通过东沟尾矿坝实测的水头数据对渗透系数进行反演分析,反演分析获得的渗透系数综合考虑了工程现场条件,此渗透系数可为该尾矿坝的安全运行和加高分析提供基础。     

Optical Fiber Polarization Interferometer for Performance Improvement in Radio-Over-Fiber Systems

An extinction ratio tunable optical fiber polarization interferometer (OFPI) is proposed and implemented to increase the optical modulation depth in radio-over-fiber (RoF) systems by suppressing the optical carrier power. The extinction ratio of the OFPI can be simply tuned by adjusting the polarization state of the launched RoF signal. Experimental results illustrate that the receiver sensitivity and dynamic range of RoF systems are greatly improved using the proposed scheme.