一种VP的快速故障恢复方法

ATM层的故障恢复技术是ATM网络管理所涉及的内容之一。本文在简单介绍了故障恢复的概念和恢复方法的研究现状基础上,提出了一种用于恢复ATM层的VP故障的快速恢复方法,即“多点”式自愈恢复算法,并进行了软件模拟和性能分析。     

Porous Ti4O7 Particles with Interconnected‐Pore Structure as a High‐Efficiency Polysulfide Mediator for Lithium–Sulfur Batteries

Multifunctional Ti₄O₇ particles with interconnected‐pore structure are designed and synthesized using porous poly(styrene‐b ‐2‐vinylpyridine) particles as a template. The particles can work efficiently as a sulfur‐host material for lithium–sulfur batteries. Specifically, the well‐defined porous Ti₄O₇ particles exhibit interconnected pores in the interior and have a high‐surface area of 592 m² g^?1; this shows the advantage of mesopores for encapsulating of sulfur and provides a polar surface for chemical binding with polysulfides to suppress their dissolution. Moreover, in order to improve the conductivity of the electrode, a thin layer of carbon is coated on the Ti₄O₇ surface without destroying its porous structure. The porous Ti₄O₇ and carbon‐coated Ti₄O₇ particles show significantly improved electrochemical performances as cathode materials for Li–S batteries as compared with those of TiO₂ particles.     

聚苯乙烯-聚4-乙烯基吡啶-稀土铕(Ⅲ)发光配合物的微观结构及荧光性能表征

含共轭结构氮杂环的非离子嵌段共聚物能与铕(Ⅲ)络合反应形成发光配合物,研究了该发光配合物的配位结构及其荧光性能。以聚苯乙烯-聚4-乙烯基吡啶(PS-b-P4VP)作为高分子配体,以邻菲罗啉(Phen)作为小分子配体,通过吡啶环的氮原子与Eu(Ⅲ)离子配位发生络合反应形成了以网状的Eu(Ⅲ)-P4VP核层以及PS链段为壳层的共聚物-稀土配合物,通过电子透射电镜(TEM)分析了其微观形态结构。用荧光分光光度计分别表征了嵌段聚合物-稀土铕(III)配合物不同链段的荧光发光强度并且进行了荧光强度的对比。此外,还研究了不同的Eu(Ⅲ)离子浓度对荧光强度的影响,得到了制备共聚物-稀土配合物荧光的最佳Eu(Ⅲ)离子浓度。     

曼哈顿世界环境下消失点非线性优化估计算法

目的 符合曼哈顿假设的结构化场景简称曼哈顿世界,具有丰富的场景结构特征。消失点作为直线的潜在观测,是一种全局信息,可以显式地体现载体坐标系与世界坐标系之间的姿态关系。为更加准确地估计消失点,本文针对单目图像,同时考虑实时性和准确性,提出了具有更高精度的基于非线性优化的消失点估计算法。方法 分析目前性能最优的基于随机采样一致性（random sample consistency,RANSAC）的消失点估计方法,通过对直线单参数化、利用正交性约束生成候选假设以及RANSAC过程的重点分析与改进,更加快速准确地得到消失点估计,为后续优化提供初值。利用直线分类时计算的误差度量构建最小二乘优化模型,采用非线性优化方法迭代求解,并采用鲁棒核函数保证迭代的精确性和结果的最优性。结果 通过仿真实验和基于公共数据集的实验对本文提出算法与目前性能最优算法进行比较。仿真实验中,相比于RCM（R3_CM1）及RCMI（R3_CM1_Iter）,本文算法结果在轴角形式下的角度偏差减小了24.6%;有先验信息约束时,角度偏差降低一个数量级,仅为0.06°,精度大幅提高。在YUD（York urban city databbase）数据集中,本文算法相较于RCM和RCMI,角度偏差分别减小了27.2%和23.8%,并且80%的消失点估计结果角度偏差小于1.5°,性能明显提升且更具稳定性。此外,本文算法在仿真实验对每一图像帧的平均优化耗时为0.008 s,可保证整体的实时性。结论 本文提出的消失点估计算法,对基于RANSAC的方法进行了改进,在不影响实时性的基础上,估计结果更加准确、鲁棒,并且更具稳定性。     

Side-chain alkylation of 2,6-lutidine to 2,6-divinylpyridine over basic zeolites

Synthesis of 2,6-divinylpyridine (2,6-DVP) and 2-methyl-6-vinylpyridine (2M6VP) was achieved for the first time by side-chain alkylation of 2,6-lutidine using formaldehyde (37 wt/v) as alkylating agent in heterogeneous conditions at atmospheric pressure, and at a reaction temperature of 300 °C over alkali and alkaline metal ion modified zeolites. A mixture of 2,6-divinylpyridine and 2-methyl,6-vinylpyridine were formed by the alkylation of the 2,6-lutidine over Li, Na, K, Rb, Cs, Mg, Ca, Sr and Ba metal ion modified zeolites. The catalytic activity of 2,6-lutidine was studied over various potassium metal ion modified zeolite molecular sieves like ZSM-5 (30), X, Y, mordenite and MCM-41. Alkali modified ZSM-5 (30) catalyst was found more active in side-chain alkylation of 2,6-lutidine when compared to other zeolites. Among all these catalysts studied K modified ZSM-5 (30) gave best conversion of 2,6-lutidine and selectivity to 2-methyl,6-vinylpyridine. K-ZSM-5 (30) catalyst was employed to study the reaction parameters like reaction temperature, weight hourly space velocity, molar ratio, and time on stream for 2,6-lutidine. The effect of potassium metal ion content and precursors of potassium ion on catalytic activity in side-chain alkylation of 2,6-lutidine was studied. The bifunctional catalyst is required containing medium or weak acidic centers and basic centers in the side-chain alkylation, which is understood through proposed mechanism. The selectivities of 2,6-DVP were 45.2, 40.0, and 30.7% at 73.4, 66.0 and 60.5% conversion at 300 °C from 2,6-lutidine and formaldehyde over K-ZSM-5 (30), Rb-ZSM-5 (30) and Cs-K-ZSM-5 (30), respectively.     

Functionalized Multi-Wall Carbon Nanotubes Enhance Transfection and Expression Efficiency of Plasmid DNA in Fish Cells

DNA vaccines are considered to be the most promising method against infectious diseases in the aquaculture industry. In the present study, we investigated the potency of ammonium group-functionalized multi-walled carbon nanotubes (MWCNTs) in enhancing the transfection and expression efficiency of plasmid DNA (pEGFP-vp5) in Ctenopharyngodon idellus kidney (CIK) cells. Agarose gel shift assay results show that ammonium group-functionalized carbon nanotubes are able to condense DNA in varying degrees. Scanning electron microscope (SEM) images shows that CIK cells show a great affinity for MWCNTs-NH₃⁺ and the CNTs covering the cell surface tend to orient their tips perpendicularly to the cell surface, and appear to be “needle-pricking the cells”. Transmission electron microscope (TEM) images confirmed that MWCNTs-NH₃⁺ penetrate the cell membranes and are widely dispersed in the CIK cell. Real-time PCR was used to detect the transfection efficiency through the expression of the outer capsid protein (VP5). The results showed that the MWCNTs-NH₃⁺:DNA complexes are able to transfect CIK cells effectively at different charge ratio than naked DNA. Subsequent studies confirmed that both functional groups and charge ratio are important factors that determine the transfection efficiency of plasmid DNA. All these results indicated that MWCNTs-NH₃⁺:DNA complexes could be suitable for developing DNA vaccine for the control of virus infection in the aquaculture industry.     

靶向肠道病毒71型VP1基因的siRNA表达质粒的构建

目的构建靶向肠道病毒71型(EV71)VP1基因的siRNA表达质粒,并进行鉴定。方法构建靶向EV71VP1基因的siRNA表达质粒pSVSi1、pSVSi2和pSVSi3;脂质体法转染A549细胞株,筛选阳性克隆,通过荧光定量PCR和Western blot,分别在mRNA水平和蛋白水平鉴定EV71VP1基因的表达。结果质粒pSVSi1、pSVSi2和pSVSi3经测序证明构建正确。pSVSi1对A549细胞VP1基因的抑制效果最好,在mRNA和蛋白水平上的抑制率分别为87%和89%,pSVSi2和pSVSi3在mR-NA水平上的抑制率分别为60%和70%。结论已成功构建了靶向EV71VP1基因的siRNA表达质粒,并筛选出一种对VP1基因有显著抑制作用的siRNA,为手足口病的siRNA基因治疗奠定了基础。     

Dynamic study of polystyrene-block-poly(4-vinylpyridine) copolymer in bulk and confined in cylindrical nanopores

AAO template is highly recommended to nanostructure polymers and to study polymer properties under confinement. The dynamic properties of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) under confinement using broadband dielectric spectroscopy are investigated in this work and the results compared to those of the bulk. Anodized aluminum oxide (AAO) membranes, having pore diameters from tens to hundreds of nanometers in size, were used to confine PS-b-P4VP. Moreover, the influence of gold nanoparticles (AuNPs) in the copolymer matrix was also studied. The morphology and structure of the bulk copolymer and the copolymer confined in the AAO templates were characterized by transmission electron microscopy, scanning electron microscopy and Small Angle X-Ray Scattering. For PS-b-P4VP in bulk, dielectric relaxation techniques allowed studying selectively the P4VP segmental dynamics within the diblock. At high temperature this copolymer presents a dominant peak (MWS relaxation), most likely originated by the relatively high conductivity combined with the presence of interfaces emerging in the nanostructured samples. Moreover, a pronounced β-relaxation is observed for the copolymer compared with that of pure P4VP. This is likely due to a non-negligible contribution from the α-relaxation of the PS component. The γ-relaxation is markedly different in the copolymer, which is evidenced by a distinct temperature dependence of the resulting relaxation times. When the copolymer is embedded in alumina nanopores with small pore diameters (25 and 35 nm) there are significant changes, where the tendency is going to a faster dynamics when the pore diameter decreases more likely related to the relevance of surface effects. The presence of the AuNPs in the system enhances this effect. These results are in agreement with segregated structures found in the block copolymer by TEM and SAXS.     

速度-密度关系欠定参数研究及应用

地震资料解释中很多时候需要研究速度-密度关系,当一个目标研究区缺少可靠的声波或密度测井时,Gardner公式为我们提供了一种重构这些曲线的有效途径,但是原始Gardner经验公式在解决具体问题时往往误差较大,在此基础上开展的岩石物理特征分析、预测储层结果不确定性大大增加。本文以南海北部湾盆地涠洲组地层为研究对象,探讨储层预测过程中速度-密度关系在不同岩性、不同层段情况下利用Gardner开展曲线重构时欠定参数的优化方法以及最终推荐使用结果,并经过误差分析、匹配性比较、合成地震记录及地震波阻抗反演结果分析,效果较好。该方法已经推广到南海西部海域各研究目标层组的曲线重构当中,效果良好。     

肠道病毒71型Lanzhou01株的分离及其生物学特性

目的对肠道病毒71型(Enterovirus 71,EV71)Lanzhou01株进行分离、鉴定,并分析其生物学特性,为EV71疫苗候选毒株的筛选奠定基础。方法从兰州市手足口病患者的粪便样本中分离EV71,经蚀斑克隆传代后,RT-PCR法检测其特异性;Vero细胞甲基纤维素蚀斑法分析病毒的毒力;克隆病毒的VP1基因,进行序列测定及分析;扫描电镜观察病毒的形态;以不同的MOI接种Vero细胞,观察细胞病变,并绘制病毒的增殖曲线;连续传代,分析VP1基因和氨基酸序列,并测定毒力,检测其遗传稳定性。结果经细胞传代和蚀斑克隆,获得增殖性能稳定的分离株,RT-PCR扩增产物经1%琼脂糖凝胶电泳分析可见约250bp的特异性条带;经VP1基因测序与进化树鉴定为EV71,其与浙江、深圳等地的EV71分离株的核苷酸序列同源性均大于99%,属于C4基因亚型;电镜下观察病毒颗粒为球形,直径20～30nm;该病毒在Vero细胞上培养后产生典型的细胞病变,毒力为6.8LgPFU/ml;经Vero细胞连续传30代,不同代次的病毒VP1基因序列的核苷酸序列同源性大于或等于99.6%,氨基酸序列几乎没有明显变异,毒力也无明显改变。结论已成功分离1株EV71,其生物学特性良好,为灭活疫苗的研制及疫苗候选株的筛选奠定了基础。