Dye-labelled polymer chains at specific sites: Synthesis by living/controlled polymerization

Dye-labelled polymer chains are extremely useful in many fields, such as optical imaging, signal amplification in biological diagnostics, light-harvesting and photochromic materials as well as in fluorescence studies about intra- and inter-molecular polymer chain associations, conformations and dynamics of polymer chains. However, in many cases, it is particularly useful that the dye is localized at a specific site, such as the chain-end or the junction between blocks. With the development of living/controlled polymerization techniques, end- and junction-functionalized polymers can be prepared with controlled molecular weights from a huge variety of monomers. This review highlights the state of the art in the strategies leading to one and only one precisely localized dye per polymer chain. Such dye can be introduced at three different steps of the polymerization: i) at the very beginning via the initiator or a chain transfer agent, ii) during polymerization via a functional monomer or a quencher, or iii) after polymerization via covalent binding of a dye-derivative.     

Actuation and blocking force of stacked nanocarbon polymer actuators

We have developed stacked nanocarbon polymer actuators that are composed of several nanocarbon polymer actuator films using nonwoven fabric as insulation layers. The nonwoven fabric prepared through electrospinning methods has extremely-low-density structures, which do not significantly prevent the motions of each nanocarbon actuator layer. Therefore, stacking several thin nanocarbon polymer actuators using nonwoven fabric as insulation layers is expected to increase generated force without decreasing the displacement of a one-layer actuator. We have prepared stacked actuators with one, two, three, four, and seven layers using this method. The displacement and blocking force of these actuators are measured and compared with those of one-layer actuators of different thicknesses. Displacement is weakly dependent on the thickness of the actuator films of the stacked actuators. On the contrary, it decreases considerably as the thickness of the actuator film of the one-layer actuator increases. In both cases, blocking force is proportional to the thickness of actuator films. We have developed a stacked actuator model based on a trilayer actuator model and confirmed the experimental results using the model.     

关于镁合金中长周期有序结构的研究综述

系统地介绍了6H、10H、14H、18R、24R型LPSO结构的原子堆垛和RE、Zn的占位特点,探讨了LPSO结构的形成条件和形成机制,分析了含LPSO结构相合金的组织演变过程并概述了组织演变方面最新的研究成果,总结了含LPSO结构相镁合金的室温和高温性能的研究现状,最后对该类合金未来的研究方向进行了展望。     

电力系统暂态稳定评估组合模型的比较

组合模型能提高电力系统暂态稳定评估的分类性能。文中构建了12组输入特征,在IEEE 16节点和IEEE 50节点测试系统上生成了24个样本集。提出了一种测试分类综合指标。在24个样本集上比较了单个(神经网络、决策树、K最近邻法和支持向量机)和组合(装袋、提升、堆栈和随机森林)的暂态稳定评估模型测试指标发现,单个评估模型中,K最近邻法分类性能最好;组合方法均能提高分类性能,其中随机森林分类性能最好,其次是堆栈(支持向量机、K最近邻法、决策树)、提升-决策树和装袋-决策树。     

虚拟弧齿锥齿轮齿面可控性椭球抛物面误差的叠加新方法

为了研究弧齿锥齿轮测量精度稳定性及不同程序测量误差的问题,提出了一种对虚拟弧齿锥齿轮进行可控误差叠加的方法.分析虚拟弧齿锥齿轮建立时产生的误差,在虚拟工件上叠加可控的椭球抛物面误差,调用OpenGL图形库中的函数将叠加误差后的效果进行直观对比.研究结果表明:对虚拟弧齿锥齿轮进行误差可控的叠加,得到了齿面误差可控的虚拟弧齿锥齿轮.     

Evolving Stacked Time Series Predictors with Multiple Window Scales and Sampling Gaps

We apply evolutionary programming to search for the optimal combination of stacked time series predictors with multiple window scales and sampling gaps. In this approach, the evolutionary process is ensured to proceed smoothly towards the optimal solution by using a control strategy based on the similarity level between the genotypes from two successive generations. Our experiments on both sunspots and S&P500 price index predictions demonstrate that this method significantly improves the prediction accuracy compared with the constrained least squared regression.     

Collapse behavior evaluation of hybrid thin-walled member by stacking condition

The recent trend of vehicle design aims at crash safety and environmentally-friendly aspect. For the crash safety aspect, the energy absorbing members should absorb collision energy sufficiently but for the environmentally-friendly aspect, the vehicle structure must be light weight in order to improve the fuel efficiency and reduce the tail gas emission. Therefore, the light weight of vehicle must be achieved in a securing safety status of crash. An aluminum or carbon fiber reinforced plastics (CFRP) is rep...     

The influence of temperature on stacking fault energy in Fe-based alloys

Temperature has great influence on the stacking fault energy (SFE). Both SFE and dr0/ d T for Fe-based alloys containing substitutional or interstitial atoms increase with increasing tempera-ture. Based on the thermodynamic model of SFE, the equation dr0/dT=drcn/dT+drseg/dT+drMG/dT and thoseexpressions for three items involved are established. The calculated dr0/dT is generally consistent with the experimental. The influence of chemical free energy on the temperature dependence of SFE is almost constant, and is obviously stronger than that of magnetic and segregation contributions. The magnetic transition and the segregation of alloying elements at stacking faults cause a decrease in SFE of the alloys when temperature increases; that is, drMG/dT<0 and dyseg/dT<0. Meanwhile, such an influence decreases with increasing temperature, except for the drseg/d 7 of Fe-Mn-Si alloys. With these results, the experimenal phenomena that the SFE of Fe-based alloys is not zero at the thermo-dynamically equilibrated tem     

叠前深度偏移技术在深层火山岩成像中的应用

针对松辽盆地深层火山岩成像不清楚的问题,应用叠前深度偏移技术,对某工区三维地震资料进行处理,结果表明,叠前深度偏移技术对于解决松辽盆地深层火山岩成像有明显效果,成像精度得到提高,火山岩与围岩的接触关系清楚,内部反射结构清晰,为深层天然气目标识别提供了高质量的地震剖面。从而降低了勘探风险。因此,叠前深度偏移技术在松辽盆地深层火山岩成像中具有广阔的应用前景。     

TWIP钢的研究现状

综述了TWIP(Twinning induced plasticity)钢研究的现状以及最新的进展.主要介绍现有TWP钢的成分体系,即Fe-Mn-Al-Si系、Fe-Mn-C系和Fe-Mn-Al-C系,以及各合金元素的作用;TWIP钢基于层错能的成分设计方法,层错能的计算方法及影响因素以及层错能与TWIP效应的关系.简述TWIP钢的组织特点、力学性能特点以及TWIP钢的生产加工的难点.