氮杂芳基三脚架配体及其金属超分子化合物

氮杂芳基三脚架配体可分为柔性和刚性两种，它们均有三个或三个以上的配位点，配体中配位点数目和位置的改变都会对金属超分子配合物的结构产生很大的影响。本文简单介绍了氮杂芳基三脚架配体自组装的特点及其所生成的超分子化合物的主要结构类型。     

Theoretical study on initial decomposition paths of energetic materials featuring RDX ring

The molecular properties of RDX are affected by the introduction of different functional groups, and the decomposition process of these analogues is studied in this paper. DFT method is used to study the initial decomposition reaction paths of 30 high energy materials based RDX skeleton. In the nitro cleavage reaction, the energy barrier become relatively low by introducing CH(NO₂)₂ or  C(NO₂)₃ groups on the C site of the six membered ring. In the ring opening reaction, the ring opening process is easier to proceed by introducing  NH₂ or  NHNH₂ groups on the C site of the six membered ring.     

太阳光抽运激光器抽运系统优化

太阳光抽运激光器中,抽运系统提供的太阳抽运光与激活晶体之间的耦合决定了激光输出的总体效率。使用Tracepro软件,建立了菲涅耳透镜、锥形抽运腔二级抽运系统模型,并对该系统进行优化。通过分析菲涅耳透镜焦斑能量沿轴线的分布,得到了锥形腔入射窗口的口径和窗口距菲涅耳透镜的距离。通过改变锥形抽运腔的腔长和锥度,分析晶体棒轴向抽运功率密度分布,得到了锥形腔的最佳结构,并对镜面反射腔和陶瓷腔进行了详细的介绍。     

Modeling the asymmetry in traffic flow (b): Macroscopic approach

In [H. Xu, H. Liu, H. Gong, Modeling the asymmetry in traffic flow (a): microscopic approach, J. Appl. Math. Model. (submitted for publication)], the asymmetric characteristic of traffic flow has been studied from a microscopic approach through the modeling of car-following behavior. This paper further discusses the asymmetric traffic flow modeling at the macroscopic scale. The microscopic asymmetric full velocity difference model is extended to a continuum traffic flow model to study the anisotropic characteristic and diffusive influence under various traffic conditions. In order to accurately solve the mathematical problem, a weighted essentially no-oscillatory (WENO) approach is applied. The performance of the model is then demonstrated through thorough evaluation against select classic models and field data. The macroscopic model is the first of its kind that is directly developed from an asymmetric car-following approach. The results show that the model is able to present many complex traffic phenomena observed in the field such as shock waves, rarefaction waves, stop-and-go waves and local cluster effects at a better level of accuracy than most of the existing models.     

基于三方博弈的共享汽车演化模型及策略分析

考虑共享汽车品质和共享汽车服务等因素,分别从政府、企业和出行者3个角度研究共享汽车出行策略选择,构建三方动态演化博弈模型,并对模型的策略选择及其演化路径进行分析.研究表明:当形象效用提升、管理成本降低、对私家车出行惩罚增大时,政府倾向于"监督"策略;当高端汽车的运营收益增加、低端汽车由于质量问题造成的损失增加、政府对低端汽车企业的惩罚增大时,企业倾向于提供"高端汽车"策略;当高端共享汽车出行与私家车出行收益之差增大、高端共享汽车出行与低端共享汽车出行收益之差增大、政府对共享汽车出行补贴增加时,出行者倾向于"共享汽车"策略.     

Silver-catalyzed decarboxylative homocoupling reaction for the construction of tetrafluoroethylene-bridging aromatic compounds

The Ag(I)-catalyzed decarboxylative homocoupling from the difluoroacetate has been developed to the synthesis of symmetric CF₂–CF₂ containing dimers. This radical dimerization overpasses the prefunctionalization of the substrate and provides a direct and efficient method for construction of tetrafluoroethylene bridge-linked homodimers.     

Graft copolymerization of maleic anhydride/styrene onto isotactic polypropylene using supercritical CO2

The free‐radical grafting of maleic anhydride (MAH) and styrene (St) onto isotactic polypropylene (iPP) was studied by thermal decomposition of dicumyl peroxide (DCP) using supercritical CO₂ as a solvent and swelling agent. Several effects of molar ratio of monomer, soaking temperature and time, reaction time, and reaction pressure on the graft degree were discussed. It was found that the addition of St to the grafting system as a comonomer could significantly enhance the graft degree of the grafted PP. Under the optimal reaction condition, the maximum of iPP grafting MAH and St in supercritical CO₂ medium was 10.58%. The chemical structures and properties of grafting copolymers were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The results showed that the supercritical CO₂ method had noticeable advantages over the existed method when compared, such as a lower temperature, a higher graft degree, easy separation, and environmentally benign. Copyright © 2007 John Wiley & Sons, Ltd.     

Effective medium theory applied to frequency selective surfaces on periodic substrates

We apply the effective medium theory combined with the conventional periodic method of moments （MoM） to analyze frequency selective surfaces （FSSs） on periodic and anisotropic substrates. Based on the effective medium theory, even periodic and anisotropic substrates can be considered homogeneous; thus, the Green’s function can be obtained. The resulting integral equation can then be solved by the MoM using rooftop basis functions and Galerkin testing functions. We analyze an example using this technique, and the numerical results agree with Fallahi’s full-vector semi-analytical method, showing an increasing difference between the results as the frequencies increase. These results show that the proposed method is effective for analyzing FSSs on periodic and anisotropic substrates.     

基于表面等离子体共振原理的空芯光纤传感器

设计了一种基于表面等离子体共振原理,使用空芯光纤作为光波导、外表面镀金属膜的光学材料圆柱体作为探头的新型折射率传感器。通过建立光学模型进行分析,在理论上推导出了这种传感器的传输光谱损耗公式,并针对该传感器在不同的光纤长度、探头材料、检测物质折射率等参数设置下的检测性能进行了分析,获得了各种参数对其性能的影响。由于该传感器可针对不同折射率的检测物质灵活地更换合适探头材料,相对于传统的表面等离子体共振光纤传感器,在易用性和性价比等方面具有更好的应用价值。     

C-半群的弱稳定性

引入了C-半群的个体弱稳定性和弱稳定性的概念,给出了弱稳定性的一个充分条件.