Orbital Instability of Standing Waves for the Klein-Gordon-Zakharov System

O Introduction We consider the orbital instability of standing waves for the Klein-Gordon-Zakharov system with different propagation speeds in three space dimensions     

Size effect of fullerene cages and encaged clusters in M_3N@C_(2n)

Based on the calculated findings that the sizes of encaged clusters determine the structures and the stability of C80-based trimetallic nitride fullerenes (TNFs), more extensive density functional theory calculations were performed on M3N@C68, M3N@C78 and M3N@C80 (M=Sc, Y and La). The calculated results demonstrated that the structures and stability undergo a transition with the increasing of the sizes of the cages and clusters. Sc3N is planar inside the three considered cages, Y3N is slightly pyramidal ins...     

机卡分离技术在DVB条件接入系统中的应用

介绍了数字电视广播条件接收系统的基本原理,以及机卡分离技术在DVB机顶盒中的应用.     

单支方法的收敛性

本文讨论用单支方法数值求解一类多刚性时滞微分代数方程的收敛性。我们获得了A－稳定的且p阶经典相容的单支方法（时滞部分用线性插值）的整体误差估计。     

ZnSe-ZnTe应变层超晶格远红外反射谱

本文首次报道室温下测量的分子束外延生长的ZnSe-ZnTe应变层超晶格的远红外反射谱.得到了ZnSe、ZnTe横光学声子摸.用长波长超晶格介电理论和多层吸收薄膜理论进行曲线拟合,确定Ⅱ-Ⅵ族ZnS、eZnTe材料的一些基本材料参数,如横光学声子频率、模衰减常数、模振荡强度、高频介电常数等.本文首次报道这些参数.     

Progress in fluorene-based wide-bandgap steric semiconductors

Molecular bulks are favorable for the thermal and morphological stability in organic wide-bandgap semiconducting polymers with potential applications in both information and energy electronics. In this review, we present our progress in the design of fluorene-based bulky semiconductors with a fractal four-element pattern. Firstly, we established one-pot methods to spirofluorenes, especially spiro[fluorene-9,9′-xanthene](SFX) serving as the next-generation spiro-based semiconductors. Secondly, we observed the supramolecular forces at the bulky groups and discovered the supramolecular steric hindrance(SSH) effect on polymorphisms, nanocrystals as well as device performance. Thus, a synergistically molecular attractor-repulsor theory(SMART) was proposed for the control of nanocrystal morphology, thin film phase and morphology. Thirdly, the third possible type of defects has been identified to generate green band(g-band) emission in widebandgap semiconductors by the introduction of molecular strain design of cyclofluorene. Finally, the first bulky polydiarylfluorene with highly crystalline and β conformation was achieved by an attractor-repulsor design of tadpole-shape monomer, which offered an effective platform to fabricate stable wide-bandgap semiconducting devices. All the discoveries offer the solid basis to break through bottlenecks of organic/polymer wide-bandgap semiconductors by the improvements of overall performances.     

偶氮氯膦Ⅰ分光光度法测定替米沙坦的含量

在pH=8.80的B-R弱碱性缓冲介质中,替米沙坦与偶氮氯膦Ⅰ染料反应形成离子缔合物,溶液颜色发生明显改变,最大吸收波长在558nm处,替米沙坦的浓度与溶液的变色程度呈良好的线性关系,从而建立了测定替米沙坦含量的光度法。在最大吸收波长处,替米沙坦的浓度在0～8.1×10-6mol/L范围内遵守比耳定律,表观摩尔吸光系数ε558为1.84×104L·mol-1·cm-1,检出限为8.63×10-7mol/L,研究了适宜的反应条件及影响因素。方法具有较高的灵敏度和良好的选择性,可用于市售药品、尿液及血浆中替米沙坦的测定。     

Biodegradable amphiphilic block copolymers containing functionalized PEO blocks:Controlled synthesis and biomedical potentials

A series of controllable amphiphilic block copolymers composed of poly(ethylene oxide)(PEO) as the hydrophilic block and poly(ε-caprolactone)(PCL) as the hydrophobic block with the amino terminal group at the end of the PEO chain(PCL-b-PEO-NH2) were synthesized.Based on the further reaction of reactive amino groups,diblock copolymers with functional carboxyl groups(PCL-b-PEO-COOH) and functional compounds RGD(PCL-b-PEO-RGD) as well as the triblock copolymers with thermosensitive PNIPAAm blocks(PCL-b-PEO-b-P...     

三阶色散对超高斯型脉冲传输特性的影响

从修正的非线性Schr?dinger方程出发,采用变分法,导出了在三阶色散情况下超高斯型脉冲参数随传输距离的演化方程组及其解,讨论了三阶色散对光纤中不同锐度超高斯脉冲传输特性的影响。求出了振幅与脉宽、脉宽与啁啾、啁啾与频率及中心位置之间的三个解析约束关系,得出了脉宽随传输距离演化的解析解,用龙格-库塔法进行数值求解描绘了不同锐度下三阶色散对光纤中超高斯脉冲的脉宽的影响。结果表明：超高斯型脉冲满足绝热特性,色散系数增大到0.3或脉冲前后沿锐度系数m≥3时,脉冲信号便会明显地被展宽,其周期也大幅度地变大。     

ULH-DWDM光传输关键技术研究

ULH-DWDM是长途骨干网的载体,提高传输容量和传输距离是其研究的重点。介绍了ULH-DWDM光传输系统,总结了系统的关键技术,如光放大技术、色散补偿技术、非线性抑制、码型调制技术等,并对这些技术及其研究动态作了深入分析和探讨。