Poly[[diaqua(N,N‐dimethylformamide‐κO)manganese(II)]‐μ3‐sulfato]

In the title complex, [Mn(SO₄)(C₃H₇NO)(H₂O)₂]_n, each Mn^II ion has a distorted octahedral geometry formed by three O atoms of three different sulfate groups, one O atom of a dimethylformamide ligand and two water molecules. The sulfate groups act as tridentate bridging ligands connecting the Mn^II ions into a two‐dimensional layer structure which can be regraded as a 4.8² network.     

纯锆上离子注入钇和镧后的表面分析

用金属蒸汽真空弧源，以40kV加速电压对纯锆样品分别进行了10¹⁶—10¹⁷/cm²的钇、镧离子注入，注入温度约为130℃.然后对注入样品进行表面分析.x射线光电子能谱分析表明，注入的钇以Y₂O₃形式存在，镧以La₂O₃形式存在.俄歇电子能谱表明，纯锆基体表面的氧化膜厚度随着离子注入剂量的增加而增加，当离子注入剂量达到10¹⁷/cm²时，氧化膜的厚度达到了最大值.卢瑟福背散射显示镧层的厚度约为30nm，同时直接观察到当离子注入剂量为(La+Y)10¹⁷/cm²时，纯锆样品表面发生了严重的溅射. 关键词： 纯锆 钇和镧离子共注入 卢瑟福背散射 x射线光电子能谱     

BNCT蒙特卡洛剂量计算的混合网格算法研究

在硼中子俘获治疗(BNCT)的蒙特卡洛(MC)剂量计算中,通常使用单一的网格模式,如16mm,8mm,4mm.使用细网格计算资源太大,使用粗网格,计算精度不够,为此,根据粒子穿透深度和计数量的变化梯度,采用混合网格模拟计算,达到了细网格的精度,时间仅为细网格的37%.     

中立型时滞差分方程的振性与正解存在性

本文研究了一类中立型时滞差分方程的振动性和正解存在性，获得了该方程所有解振动的“Sharp”条件及存在正解的一个充分条件．     

具有突变结构开放腔的矩阵分析

利用模式展开与场匹配原理，建立了突变波导的散射矩阵(S参数矩阵)，在此基础上分析研究了具有突变结构的波导开放式谐振腔，并由矩阵级联建立了开放腔总的S参数矩阵.通过Matlab编制计算程序对具有多级突变结构的开放式输出腔进行了数值计算和分析，并通过与实验数据和软件模拟的结果比较对该方法得到的数据结果进行了验证. 关键词： 回旋管 开放式谐振腔 突变结构 S参数矩阵     

Investigation of sulfonated poly(ether ether ketone sulfone)/heteropolyacid composite membranes for high temperature fuel cell applications

The sulfonated poly(ether ether ketone sulfone) (SPEEKS)/heteropolyacid (HPA) composite membranes with different HPA content in SPEEKS copolymers matrix with different degree of sulfonation (DS) were investigated for high temperature proton exchange membrane fuel cells. Composite membranes were characterized by Fourier transfer infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR band shifts suggested that the sulfonic acid groups on the copolymer backbone strongly interact with HPA particles. SEM pictures showed that the HPA particles were uniformly distributed throughout the SPEEKS membranes matrix and particle sizes decreased with the increment of copolymers' DS. The holes were not found in SPEEKS‐4/HPA30 (consisting of 70% SPEEKS copolymers with DS = 0.8 and 30% HPA) composite membrane after composite membranes were treated with boiling water for 24 h. Thermal stabilities of the composite membranes were better than those of pure sulfonated copolymers membranes. Although the composite membranes possessed lower water uptake, it exhibited higher proton conductivity for SPEEKS‐4/HPA30 especially at high temperature (above 100 °C). Its proton conductivity linearly increased from 0.068 S/cm at 25 °C to 0.095 S/cm at 120 °C, which was higher than 0.06 S/cm of Nafion 117. In contrast, proton conductivity of pure SPEEKS‐4 membrane only increased from 0.062 S/cm at 25 °C to 0.078 S/cm at 80 °C. At 120 °C, proton conductivity decreased to poor 0.073 S/cm. The result indicated that composite membranes exhibited high proton conductivity at high temperature. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1967–1978, 2006     

Is Kano-Nucleon Interaction Consistent with Pentaquark θ^＋

The quark-delocalization colour-screening model is employed to calculate the effective potential between nucleon and kaon. The results show that the potentials are attractive in the I = 0 channel and repulsive in the I = 1 channel. The interactions are very weak between K^＋n or K^0p due to the cancellation between I = 0 and I = 1. It is possible to have a high s-wave resonance （1615 MeV）, but the width may be too wide to be observed in the experiments.     

Method for vessel attitude estimation by spatial correlation function for bottom reverberation

Under the assumption that the sea bottom is an almost-flat and randomly rough thin layer, a spatial correlation model for bottom reverberation is constructed. At high signal noise ratio, the phase of the spatial correlation function is the product of sound wave number and the vertical vector between two hydrophones. In a nominally horizontal plane, roll and pitch bring on the vertical vector between the hydrophones. Then an equation including roll, pitch and the phase of the spatial correlation function is found. If a parallelogram can be constructed by 3 hydrophones and the rat ios of its acreage to diagonals are not smaller than half of the wavelength, roll and pitch can be obtained analytically or by optimal method. However, the ranges of roll and pitch are restricted because of the phase ambiguity. Using Fisher information matrix, the Cramer-Rao lower bound is obtained. Results from computer simulation and sea test data prove the feasibility of the method.     

BNCT优化网格设计及相关算法研究

用MCNP蒙特卡罗程序模拟了硼中子俘获治疗(BNCT)3种国际基准网格模型, 并与 修正的Snyder椭球模型进行了比较. 在此基础上, 给出了一种保质量守恒、内存量少、易于产生输入文件的4种基本材料成分的BNCT网格模型. 计算结果表明, 在4mm网格下, 新模型可以达到基准模型的精度; 根据解析模型剂量随深度的变化规律, 研究构造了多网格组合模型, 在重要区域计算精度不损失的条件下, 计算时间大大缩短. 最后研究给出了一个既保证精度、又在可接受的时间内完成剂量计算的模型、样本数和相应的算法, 它基本上满足临床BNCT的要求.