多模光纤束斑纹场的某些特性

本文研究多模光纤束斑纹场经透镜后的光场特性以及两种有应用价值的斑纹场实验。     

光纤复合架空地线

光纤复合架空地线是电力系统发展应用的一种独特通信地线,它是把光纤维通信和输电线路的架空地线复合为一体的综合电缆,既可避雷又可通信,可随输电线路同时设计施工建设,不仅节省投资,而且应用安全可靠。文章介绍了光纤复合架空地线在国内外发展应用及其主要结构形式。     

Influence of fiber and grain bridging on crack profiles in SiC fiber-reinforced alumina-matrix composites

Initial crack extension and crack propagation in sintered SiC fiber reinforced alumina matrix composites were observed in situ in the scanning electron microscope (SEM). In these composites, coupled toughening mechanisms associated with both grain and fiber bridging are operative in the crack wake. Their contribution to toughness were obtained from crack profiles measured in the crack wake at various applied loads and crack lengths. The crack profiles of the fiber reinforced samples reveal much smaller crack opening displacements compared to the monolithic samples. The fibers act as ligaments which bridge and thereby exert closure stresses on the crack surfaces. The profiles revealed pronounced reduction in the crack opening displacement (COD) around the fiber positions. Accordingly, grain bridging in the vicinity of the fibers was still operative up to an applied stress intensity factor of 5.7 MPa m^1/2 which is 30% above the maximum toughness that could be obtained with the monolithic samples for the same crack length.     

半导体吸收式光纤温度传感器的研制

本文介绍了一种应用本征半导体的禁带宽度随温度升高而减小的现象,引起对特定波长的光迁过率也产生减小的原理,以砷化镓半导体晶片作敏感元,用光纤导光系统,半导体发光二极管作光源,半导体光电二极管作光电转换元,构成了半导体吸收式光纤温度传感器并对这进行了研究,制作和实验;又阐述了这种传感器的特点和应用领域。     

用于环氧树脂固化过程实时监测的光纤折射率传感器

研究了应用光纤传感技术对环氧树脂固化过程进行实时监测的方法。通过将一段光纤的包层去掉构成光纤折射率传感器, 利用环氧树脂在固化过程中折射率随固化度增大而增大的特性进行固化监测。应用光线追迹法和局部平面波理论导出光纤固化传感器的理论模型。通过在光纤传感区一端的光纤端面镀全反射膜形成探针型传感结构。对E51 环氧树脂的等温固化过程进行了实时监测实验。      

光纤测温、毛细钢管测压系统在现场中的应用

光纤测温、毛细管测压技术是目前应用于油田测试领域较为先进的一门技术,该技术可实现任何形状复杂、环境恶劣的温度、压力等信息的在线检测和定位、阐述了光纤测温、毛细管测压系统的原理、组成及安装方式,介绍了辽河油田应用该系统在蒸汽辅助重力泄油(SAGD)试验站对生产井井下监测取得的良好效果,评价了该系统的优越性。该系统消除了传统方法所具有的"侵扰性",使以前高费用才能进行的检测或根本无法检测的完井结构的实时检测成为可能,从而获得传统监测手段无法获取的数据。     

7,8-Dihydroxiflavone Protects Adult Rat Axotomized Retinal Ganglion Cells through MAPK/ERK and PI3K/AKT Activation

We analyze the 7,8-dihydroxyflavone (DHF)/TrkB signaling activation of two main intracellular pathways, mitogen-activated protein kinase (MAPK)/ERK and phosphatidylinositol 3 kinase (PI3K)/AKT, in the neuroprotection of axotomized retinal ganglion cells (RGCs). Methods: Adult albino Sprague-Dawley rats received left intraorbital optic nerve transection (IONT) and were divided in two groups. One group received daily intraperitoneal DHF (5 mg/kg) and another vehicle (1%DMSO in 0.9%NaCl) from one day before IONT until processing. Additional intact rats were employed as control (n = 4). At 1, 3 or 7 days (d) after IONT, phosphorylated (p)AKT, p-MAPK, and non-phosphorylated AKT and MAPK expression levels were analyzed in the retina by Western blotting (n = 4/group). Radial sections were also immunodetected for the above-mentioned proteins, and for Brn3a and vimentin to identify RGCs and Müller cells (MCs), respectively (n = 3/group). Results: IONT induced increased levels of p-MAPK and MAPK at 3d in DHF- or vehicle-treated retinas and at 7d in DHF-treated retinas. IONT induced a fast decrease in AKT in retinas treated with DHF or vehicle, with higher levels of phosphorylation in DHF-treated retinas at 7d. In intact retinas and vehicle-treated groups, no p-MAPK or MAPK expression in RGCs was observed. In DHF- treated retinas p-MAPK and MAPK were expressed in the ganglion cell layer and in the RGC nuclei 3 and 7d after IONT. AKT was observed in intact and axotomized RGCs, but the signal intensity of p-AKT was stronger in DHF-treated retinas. Finally, MCs expressed higher quantities of both MAPK and AKT at 3d in both DHF- and vehicle-treated retinas, and at 7d the phosphorylation of p-MAPK was higher in DHF-treated groups. Conclusions: Phosphorylation and increased levels of AKT and MAPK through MCs and RGCs in retinas after DHF-treatment may be responsible for the increased and long-lasting RGC protection afforded by DHF after IONT.     

Adsorption of Pb2+, Cu2+ and Co2+ by polypropylene fabric and polyethylene hollow fiber modified by radiation-induced graft copolymerization

Cation-exchange adsorbents were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) fabric and polyethylene (PE) hollow fiber and subsequent phosphonation of epoxy groups of poly(GMA) graft chains. The adsorption characteristics of Pb²⁺, Cu²⁺ and Co²⁺ for the two cation-exchange adsorbents were studied. In the grafting of GMA onto PP fabric, the degree of grafting (%) increased with an increase in reaction time, reaction temperature, and pre-irradiation dose. The maximum grafting yield was observed around 60% GMA concentration. In 50, 130 and 250% GMA-grafted PP fabric, the content of phosphoric acid was 1.52, 3.40 and 4.50 mmol/g at 80 °C in the 85 % phosphoric acid aqueous solution for 24 h, respectively. The adsorption of Pb²⁺, Cu²⁺ and Co²⁺ by PP fabric adsorbent was enhanced with an increased phosphoric acid content The order of adsorption capacity of the PP fabric adsorbent was Pb²⁺>Co²⁺>Cu²⁺. In adsorption of Pb²⁺, Cu²⁺ and Co²⁺ by PE hollow fiber, the amount of Pb²⁺ adsorbed by the PE hollow fiber adsorbent containing 1.21 mmol/g of -PO₃H wasca. 54.4 g per kg. The adsorption amount of Cu²⁺ and Co²⁺ in the same PE hollow fiber wasca. 21.0 g per kg andca. 32.1 g per kg, respectively. The order of adsorption of the PE hollow fiber adsorbent was Pb²⁺>Co²⁺>Cu²⁺.     

Separation of CO2 by 2-amino-2-methyl-1-propanol aqueous solution in microporous hydrophobie hollow fiber contained liquid membrane

The absorption of CO₂ from a mixture of CO₂/N₂ gas was carried out using a flat-stirred vessel and the polytetrafluoroethylene hollow fiber contained aqueous 2-amino-2-methyl-1-propanol (AMP) solution. The reaction of CO₂ with AMP was confirmed to be a second order reversible reaction with fast-reaction region. The mass transfer resistance in the membrane side obtained from the comparison of the measured absorption rates of CO₂ in a hollow fiber contained liquid membrane with a flat-stirred vessel corresponded to about 90% of overall-mass-transfer resistance. The mass transfer coefficient of hollow fiber phase could be evaluated, which was independent of CO₂ loading.     

多模光纤声波传感器的研究

分析了多模光纤中的模式自干涉效应,给出了多模声波传感器的基本原理。通过实验取得了较好的结果。