Gamma-radiation effects in pure-silica-core photonic crystal fiber

We investigated the steady state gamma-ray radiation response of pure-silica-core photonic crystal fibers(PSC-PCFs)under an accumulated dose of 500 Gy and a dose rate of 2.38 Gy/min. The radiation-induced attenuation(RIA) spectra in the near-infrared region from 800 nm to 1700 nm were obtained. We find that the RIA at 1550 nm is related with hydroxyl(OH-) absorption defects in addition to the identified self-trapped hole(STH) defects. Moreover, it is proposed and demonstrated that reduced OH-absorption defects can decrease the RIA at 1550 nm. The RIA at 1550 nm has effectively declined from 27.7 d B/km to 3.0 dB/km through fabrication improvement. Preliminary explanations based on the unique fabrication processes were given to interpret the RIA characteristics of PSC-PCFs. The results show that the PSC-PCFs,which offer great advantages over conventional fibers, are promising and applicable to fiber sensors in harsh environments.     

腰椎运动链训练系统对腰椎间盘突出症患者术后腰椎功能与生物力学的影响

探讨腰椎运动链训练系统对腰椎间盘突出症(lumbar disc herniation, LDH)术后腰椎功能与生物力学的影响。通过选取河南省信阳市中心医院收治的122例LDH患者,随机数字表法分组,各61例。两组均行手术治疗,对照组采取常规训练,观察组基于对照组采取腰椎运动链训练系统。比较2组干预效果。干预12周后、24周后观察组健侧、弱链侧平均振幅值、步幅、步频、腰背伸展状态平均功率(AP)、腰背伸展状态平均功率(PT)高于对照组,VAS评分及腰背屈/伸比(F/E)低于对照组(P<0.05);干预24周后观察组SF-36、BI评分高于对照组(P<0.05)。腰椎运动链训练系统可缓解LDH术后疼痛,改善下肢步态,恢复腰椎功能及生物力学,提高生活质量。     

1,3-丁二烯掺混丙炔热解中芳烃生成的协同效应理论研究

A numerical investigation on the co-pyrolysis of 1,3-butadiene and propyne is performed to explore the synergistic effect between fuel components on aromatic hydrocarbon formation.A detailed kinetic model of 1,3-butadiene/propyne co-pyrolysis with the sub-mechanism of aromatic hydrocarbon formation is developed and validated on previous 1,3-butadiene and propyne pyrolysis experiments.The model is able to reproduce both the single component pyrolysis and the co-pyrolysis experiments,as well as the synergistic effect between 1,3-butadiene and propyne on the formation of a series of aromatic hydrocarbons.Based on the rate of production and sensitivity analyses,key reaction pathways in the fuel decomposition and aromatic hydrocarbon formation processes are revealed and insight into the synergistic effect on aromatic hydrocarbon formation is also achieved.The synergistic effect results from the interaction between 1,3-butadiene and propyne.The easily happened chain initiation in the 1,3-butadiene decomposition provides an abundant radical pool for propyne to undergo the H-atom abstraction and produce propargyl radical which plays key roles in the formation of aromatic hydrocarbons.Besides,the 1,3-butadiene/propyne co-pyrolysis includes high concentration levels of C3 and C4 precursors simultaneously,which stimulates the formation of key aromatic hydrocarbons such as toluene and naphthalene.     

买方抗衡势力对上游企业定价形式决策的影响——基于讨价还价博弈的分析

基于上游垄断、下游双寡头竞争的纵向市场结构,在讨价还价博弈的框架下,构建了下游零售商均无买方抗衡势力和单个零售商具有买方抗衡势力两种情况下的,上游供应商最优定价形式决策模型,分析了买方抗衡势力对供应商定价形式决策的影响。研究发现:从供应商利润角度来说,当零售商均无买方抗衡势力时,两部收费制和RPM(转售价格维持)是等价的,且都优于线性定价;当单个零售商具有买方抗衡势力时,RPM优于两部收费制,同时也优于线性定价,但是两部收费制与线性定价之间的关系不确定。在此结论之上,本文还讨论了政府对RPM采用不同规制政策时,供应商最优的定价形式选择。     

基于涡流脉冲相位热成像的金属材料裂纹检测

涡流热成像可以对金属材料表面、近表面缺陷进行快速准确的检测。采用涡流热成像与脉冲相位分析相结合的方法,针对裂纹附近相位谱的分布规律及温度场对相位谱的影响关系问题,分别对带有上表面裂纹和下表面裂纹的45#钢料进行感应加热仿真和实验分析。结果表明,相位谱分布与温度大小无关,只与温度变化趋势有关,相位谱图对不均匀加热有很好的抑制作用,可以扩大裂纹的检测范围,当频率低于12.5 Hz时能够清晰地识别裂纹。结合实验验证了仿真结论的正确性,为下一步利用相位信息实现缺陷的定量检测提供参考。     

先驱体浸渍裂解结合反应熔渗法制备Cf/ZrC-SiC复合材料

以先驱体浸渍裂解结合反应熔渗工艺将Cf/C-SiC材料内部富余的自由碳相转变为ZrC超高温陶瓷,制备了Cf/ZrC-SiC复合材料.对Cf/C-SiC基材的孔隙进行了设计,利用XRD和SEM分析了Cf/ZrC-SiC复合材料的微观结构和物相组成.结果表明:采用PIP法可制备具有理想孔隙率的Cf/C-SiC基材;1800℃熔渗Zr-Si合金反应制得的Cf/ZrC-SiC材料主要由SiC和ZrC相组成;高温条件下熔融金属与基体反应的同时,还会侵蚀碳纤维.热解碳涂层能保护纤维.     

一种基于苯并噁唑类的可视化检测汞离子的荧光探针

设计合成了一种用于检测Hg²⁺的苯并噁唑类荧光探针4-(苯并[d]噁唑-2-基)-2-((二(2-(乙巯基)乙基)氨基)甲基)苯酚(ZY1), 用质谱、核磁氢谱和X射线单晶衍射等方法对其进行了结构表征, 并考察了其光谱性能. 研究结果表明, ZY1对Hg²⁺有较高的选择性和灵敏度, 它们之间的结合比为1:1, 共存离子及pH值(3.0～9.0)对其测定影响小. ZY1能够可视化检测Hg²⁺, 并在HeLa活细胞中实现了汞离子的成像, 这对检测生物体内的Hg²⁺将具有潜在的应用价值.     

金属电极对有机分子非弹性电子隧穿谱的影响

利用第一性原理计算金属电极下1,6-己二硫醇和1,4-二巯基苯分子结的非弹性电子隧穿谱,发现非弹性电子隧穿谱对金属电极的变化十分灵敏,并且非弹性电子隧穿谱的振动峰位置和强度与硫原子和金属电极表面的距离密切相关.结果表明电极材料和分子与金属成键的情况是影响分子结的非弹性电子输运的重要因素.理论分析进一步表明不同金属电极和有机分子的耦合能不同导致了谱峰强弱的调整.     

基于实验研究的轧机垂扭耦合振动分析

以承钢1780热连轧机组的R1为研究对象,依据多自由度系统振动理论,提出了一种垂扭耦合动力学模型的建模方法,建立了R1的垂扭耦合振动微分方程;并结合现场实测数据,确定了系统的耦合系数;分别计算了该轧机垂振、扭振、垂扭耦合振动的固有频率,并进行了比较。分析了考虑耦合振动系统时,轧机固有频率的变化情况,给出了R1垂扭耦合振动的前15阶固有频率。通过对咬钢激励情况下垂扭耦合系统的动态响应分析,分别计算了上下辊系扭振与垂振的最大振幅。通过对振动幅值的比较,论证了扭振与垂振之间的影响程度,并通过现场实测对理论分析结果进行了验证。     

Spin noise spectroscopy of rubidium atomic gas under resonant and non-resonant conditions

The spin fluctuation in rubidium atom gas is studied via all-optical spin noise spectroscopy(SNS).Experimental results show that the integrated SNS signal and its full width at half maximum(FWHM) strongly depend on the frequency detuning of the probe light under resonant and non-resonant conditions.The total integrated SNS signal can be well fitted with a single squared Faraday rotation spectrum and the FWHM dependence may be related to the absorption profile of the sample.