The Influence of Space Restriction on the Mechanical Properties of Isotactic Polypropylene/Reduced Graphene Oxide Nanocomposite Injection Bars

Isotactic polypropylene (iPP)/reduced graphene oxide (RGO) nanocomposite bars were prepared by injection molding and the effects of RGO on the iPP matrix were investigated via differential scanning calorimetry, two dimensional wide angle X-ray diffraction (2D WAXD) and small angle X-ray scattering (2D SAXS) techniques. It is demonstrated that RGO is an effective nucleation agent for iPP and the incorporation of RGO can enhance the degree of orientation of iPP crystals at flow direction. Furthermore, the orientation of iPP chains at flow direction intensifies with the increase of RGO contents, which can be attributed to that RGO obstructed the motion of orientated polymer chains. Although the enhancement effect is weaker than that of High density polyethylene (HDPE)/RGO nanocomposites with epitaxial crystallization, the mechanical properties of iPP/RGO nanocomposites can also be improved apparently.     

Synthesis and Crystal Structure of a Novel Ion-pair Compound Consisting of 1-（4-Bromobenzyl）pyridinium Cation and 7,7,8,8-Tetracyanoquinodimethanide Anion

The title compound [BrBzPy][TCNQ] （BrBzPy^＋=1-（4-bromobenzyl）pyridinium cation, TCNQ = 7,7,8,8-tetracyanoquinodimethanide anion） was synthesized by the reaction of [BrBzPy]Br and LiTCNQ in ethanol solution and its structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c with a = 14.067（3）, b = 7.3089（14）, c = 23.796（4）A, β = 122.011（9）°, V= 2074.6（7）A^3, Z = 4, C24H15BrN5, Mr = 453.32, Dc = 1.451 g/cm^3,μ = 2.002 mm^-1, S = 1.047, F（000） = 916, R = 0.0398 and wR = 0.0921. The most prominent structural features are the completely segregated stacking columns of the TCNQ- anions and [BrBzPy]^＋ cations. In a TCNQ column, the centroid-to-centroid distances of the neighboring anions of TCNQ are 3.2693 and 4.9464 A, respectively.     

无光滤波六倍频微波信号产生的系统设计

基于两个级联偏振调制器,提出了一种高频谱纯度、稳定的六倍频微波信号产生方法。该方法通过适当调整偏振片的偏振方向、射频驱动信号电压和相位,实现无光滤波器条件下、任何波段六倍频微波信号的产生。利用Optisystem平台搭建的仿真系统,以S波段4 GHz信号为例,验证了该设计系统产生的六倍频信号质量,并分析了非理想射频驱动电压和相位对六倍频信号质量的影响,结果表明:该设计系统能产生最大光边带抑制比、射频无杂散抑制比分别为21.3,15.2 dB的六倍频微波信号;且非理想驱动电压和相位差的偏离应控制在理想值5%的范围之内。     

一簇金刚石晶格上S~4模型的相变

采用重整化群和累积展开的方法,研究了一簇金刚石晶格上S~4模型的相变,求得了系统的临界点.结果表明:当分支数m=2和m 12时,该系统只存在一个Gauss不动点K~*=b_2/2, u_2~*=0;当分支数3≤m≤12时,该系统不仅有Gauss不动点,还存在一个Wilson-Fisher不动点,并且后一个不动点对系统的临界特性产生决定性的影响.     

一类广义非线性强阻尼扰动发展方程的行波解

研究了一类非线性强阻尼广义扰动发展方程问题.它们在数学、力学、物理学等领域中广泛出现.首先,引入一个行波变换,把相应的偏微分方程问题转化为行波方程问题并求出原典型问题的精确解.再用小参数方法和引入伸长变量构造了问题的渐近解.最后, 用泛函分析的不动点理论证明了原非线性强阻尼广义扰动发展方程初值问题渐近行波解的存在性,并证明渐近解具有较高的精度和一致有效性.该文求得的渐近解是一个解析展开式, 所以它还可继续进行解析运算, 而单纯用数值模拟的方法是不行的.     

Fabrication of high-efficiency multilayer-coated gratings for the EUV regime using e-beam patterned substrates

The use of multilayer reflection coatings has proven to be an effective means for improving the efficiency of soft X-ray and extreme ultraviolet gratings. These techniques have recently been extended to e-beam-patterned binary blazed substrates. Here we present further refinement of the e-beam-patterned substrate method, demonstrating near normal-incidence reflection efficiencies as high as 41% into the first-diffracted order.     

配位聚合物[Zn(PDA)(obix)]的合成、晶体结构和荧光性质

Hydrothermal reaction between 1,4-phenylenediacetic acid (H₂PDA) and Zn(NO₃)₂·6H₂O at the presence of the second ligand of 1,2-bis((1H-imidazol-1-yl) methyl)benzene (obix) yields a new 2D metal-organic coordination polymer [Zn(PDA)(obix)] (1), which has been characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and thermal analysis. Complex 1 presents a two-dimensional (2D) sheet structure and displays strong luminescent emission at room temperature. CCDC: 716984.     

基于原位反应合成的一个锌的配位聚合物

A coordination polymer of Zn(IBT)2 (2) (HIBT=5-(4-((1H-imidazol-1-yl)methyl)phenyl)-2H-tetrazole) has been prepared by hydrothermal method and characterized by IR spectroscopy,elemental analysis and single-crystal X-ray diffraction structure analysis. Compound 2 has one-dimensional (1D) hinged chain structure and displays strong photoluminescent emission at room temperature.     

新型N，O-双官能团席夫碱配体及其镉配合物的合成、晶体结构及荧光性质

合成了一个新颖的席夫碱N,O-双管能团有机配体(4-(吡啶基-2-亚甲基氨基)苯甲酸,4,2-pmabaH) (1),并在水和乙醇体系中合成了它的镉配合物[Cd(4,2-pmaba)(H₂O)₃](4,2-pmaba)·H₂O (2)。利用元素分析及X-射线单晶结构测定对其进行了表征。标题化合物1属于正交晶系,Pna2₁空间群。化合物2属于正交晶系,Pbcn空间群。在化合物2中,Cd(Ⅱ)的配位环境为七配位。其中有2种不同配位模式的配体,其M₂L₂环状结构单元通过氢键作用连接成一个具有三维结构的超分子化合物。对化合物1,2的荧光性质也进行了测定。     

Coarse-graining Calcium Dynamics on Stochastic Reaction-diffusion Lattice Model

We develop a coarse grained (CG) approach for efficiently simulating calcium dynamics in the endoplasmic reticulum membrane based on a fine stochastic lattice gas model. By grouping neighboring microscopic sites together into CG cells and deriving CG reaction rates using local mean field approximation, we perform CG kinetic Monte Carlo (kMC) simulations and find the results of CG-kMC simulations are in excellent agreement with that of the microscopic ones. Strikingly, there is an appropriate range of coarse proportion m, corresponding to the minimal deviation of the phase transition point compared to the microscopic one. For fixed m, the critical point increases monotonously as the system size increases, especially, there exists scaling law between the deviations of the phase transition point and the system size. Moreover, the CG approach provides significantly faster Monte Carlo simulations which are easy to implement and are directly related to the microscopics, so that one can study the system size effects at the cost of reasonable computational time.