A novel polarization splitter in ZnTe tellurite glass three-core photonic crystal fiber

A kind of polarization splitter in ZnTe tellurite glass three-core photonic crystal fiber has been proposed. The polarization splitter is based on the phenomenon of resonant tunneling. We use the finite element method and the full-vector beam propagating method to analyze the characteristics of three-core photonic crystal fiber. Compare with the silica glass three-core PCF, the ZnTe tellurite glass three-core PCF have higher extinction ratios and lower coupling loss, the extinction ratios ERA = ? 164.2681 dB and ERC = ? 37.1742 dB at the wavelength λ = 1.55 μm, and the coupling loss is lower than 0.02 dB. The 8.7983-mm-long splitter is proposed to achieve extinction ratio better than ? 20 dB and a bandwidthof 20 nm.     

基于混合交叉进化算法的混沌系统参数估计

提出一种混合交叉进化算法 来估计混沌系统的未知参数. 首先通过构造一个适当的适应度函数, 将混沌系统的参数估计问题转化为一个多维的优化问题. 在混合交叉进化算法中, 利用佳点集方法初始化种群, 增加了算法的稳定性和全局搜索能力. 在进化过程中, 混合交叉操作既能指导种群个体向最优解子空间靠近, 又能提高算法跳出局部最优的能力, 从而协调了算法的勘探和开采能力. 以几个标准测试函数和典型的Lorenz混沌系统为例进行仿真实验, 结果表明了该方法的有效性.     

Cr2MC(M=Al, Ga)的电子结构、弹性和热力学性质的第一性原理研究

本文使用第一性原理的GGA/RPBE方法研究了Cr₂MC(M=Al, Ga)的电子结构、弹性和热力学性质. 研究发现两个化合物的体积压缩性几乎相同, 并且证实了在0—50 GPa范围内c轴始终较a轴更难以压缩并且结构始终是稳定的. 通过对内坐标的研究发现了Cr₂AlC中Cr离子的内坐标始终大于Cr₂GaC中Cr离子的内坐标. 使用准谐德拜模型得到的体弹模量在0 GPa下随着温度的升高而减小, 而在300 GPa下则随着温度的升高而增大. 对德拜温度的研究发现Cr₂GaC的值小于Cr₂AlC的值, 而对热膨胀系数、Grüneisen参数、熵和热容的计算发现Cr₂GaC的值大于Cr₂AlC的值. 对电子结构的分析发现Cr₂GaC的s和p电子在费米能级处的值大于Cr₂AlC的s和p电子的值, 而其他离子的电子分布几乎一致.     

氧原子在Pt(111)表面和次表层的吸附与扩散

氧原子在Pt表面的吸附和扩散是理解氧化和腐蚀等问题的基础.基于密度泛函理论和周期平板模型研究了氧原子在Pt(111)表面及次表层的吸附,通过扫描隧道显微镜(STM)的理论计算分析了吸附的结构特征.采用CI-NEB方法讨论了氧原子在Pt(111)表面和次表层的扩散过程.研究结果表明氧原子在Pt(111)表面的扩散比较容易,而氧原子向次表层的扩散相对较难,这主要是因为次表层的扩散需要经过一个Pt原子层,必须克服一定的能垒,从而说明过渡金属Pt具有很强的抗氧化性.     

First-principles calculation of the lattice compressibility, elastic anisotropy and thermodynamic stability of V2GeC

We investigate the elastic and the thermodynamic properties of nanolaminate V2GeC by using the ab initio pseudopotential total energy method.The axial compressibility shows that the c axis is always stiffer than the a axis.The elastic constant calculations demonstrate that the structural stability is within 0-800 GPa.The calculations of Young’s and shear moduli reveal the softening behaviour at about 300 GPa.The Possion ratio makes a higher ionic or a weaker covalent contribution to intra-atomic bonding and the degree of ionicity increases with pressure.The relationship between brittleness and ductility shows that V2GeC is brittle in ambient conditions and the brittleness decreases and ductility increases with pressure.Moveover,we find that V2GeC is largely isotropic in compression and in shear,and the degree of isotropy decreases with pressure.The Grüneisen parameter,the Debye temperature and the thermal expansion coefficient are also successfully obtained for the first time.     

Schumann,a modeling framework for supply chain management under uncertainty

We present a modeling framework for the optimization of a manufacturing, assembly and distribution (MAD) supply chain planning problem under uncertainty in product demand and component supplying cost and delivery time, mainly. The automotive sector has been chosen as the pilot area for this type of multiperiod multiproduct multilevel problem, but the approach has a far more reaching application. A deterministic treatment of the problem provides unsatisfactory results. We use a 2-stage scenario analysis based on a partial recourse approach, where MAD supply chain policy can be implemented for a given set of initial time periods, such that the solution for the other periods does not need to be anticipated and, then, it depends on the scenario to occur. In any case, it takes into consideration all the given scenarios. Very useful schemes are used for modeling balance equations and multiperiod linking constraints. A dual approach splitting variable scheme is been used for dealing with the implementable time periods related variables, via a redundant circular linking representation.     

色酮吡唑啉酮类衍生物的合成及抗白血病细胞活性

以色酮-吡唑啉酮作为C1合成子, 在5 mol% 的DBU催化下,与α,β-不饱和酮发生Michael加成反应, 获得了10个色酮吡唑啉酮类衍生物3a~3j,产率76%~90%, dr值为4/1~9/1, 其结构经¹H NMR, ¹³C NMR和HR-MS（ESI-TOF）表征,通过单晶进一步进行了确定化合物3b的相对构型。该类化合物包含有连续两个立体中心,包括一个季碳中心,可以为生物活性筛选提供物质基础。采用MTT法研究了3a~3f对人白血病细胞(K562)的体外抗增殖活性。结果表明：化合物3a, 3c, 3d和3i对K562增殖具有一定的抑制活性。     

新型异噁唑拼接三氟甲基螺环吡咯氧化吲哚类化合物的合成

以靛红衍生的三氟甲基亚胺与硝基异噁唑苯乙烯为原料,在有机碱DABCO催化作用下,发生[3+2]环加成反应,获得合成了15个新颖的异噁唑拼接三氟甲基螺环吡咯氧化吲哚类化合物3a~3o,产率71%~90%,dr值>20/1, 其结构经¹H NMR, ¹³C NMR和HR-MS（ESI-TOF）表征,化合物3f的相对构型通过单晶进一步进行了确定。该类化合物含有连续4个立体中心,包括一个螺环季碳中心。      

常春藤皂苷元-半酯-AZT衍生物的合成及抗病毒蛋白酶活性

以常春藤皂苷元为原料,合成了5个常春藤皂苷元-半酯-AZT复合物,其结构经¹HNMR、¹³CNMR和ESI-MS表征。并对所有目标分子体外抗HIV-1和HCV NS3/4A蛋白酶的活性进行了初步评价,化合物5显示较强的抗HCV NS/4A蛋白酶的活性,IC₅₀=5.8 μM,其余化合物IC₅₀为10.6～42.3 μM。所有衍生物无抗HIV蛋白酶活性,揭示该类衍生物选择性抑制HCV NS3/4A蛋白酶。