矩阵方程（A^TXA，B^TXB=（C，D）的反对称解及其最佳逼近

本利用矩阵对的标准相关分解，得到了矩阵方程(A^TXB，B^TXB)=(C，D)反对称解存在的充分必要条件及通解表达式，同时给出了解关于已知矩阵的最佳逼近．     

Navier-Stokes方程带Backtracking技巧的两重网格算法

1 引 言考虑二维不可压 Navier-Stokes方程:     

Competitive influence of atactic polystyrene and supercritical carbon dioxide on the conformation of syndiotactic polystyrene

The crystallization behavior of miscible syndiotactic polystyrene (sPS) and atactic polystyrene (aPS) blends with different sPS/aPS weight ratios was investigated in supercritical CO₂ by using Fourier‐transform infrared spectroscopy, differential scanning calorimetry, and wide‐angle X‐ray diffraction. Supercritical CO₂ and aPS exhibited different effects on the conformational change of sPS and competed with each other. Increasing the content of amorphous aPS in the blends made its effect on the conformational change of sPS gradually surpass that of supercritical CO₂. Supercritical CO₂ favored the formation of the helical conformation of sPS in lower temperature range and the all trans planar conformation in higher temperature range, instead of forming the latter one only in higher temperature range in ambient atmosphere. However, increasing aPS content in the blends pushed the range for forming the helical conformation to lower temperature and made the all trans planar conformation dominant in aPS/sPS 25/75 blend after treating in supercritical CO₂ above 60 °C. The all trans planar zigzag conformation was more favorable than the helical conformation after mixing aPS in sPS in supercritical CO₂. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1755–1764, 2007     

回填材料膨润土对放射性气体滞留能力模拟研究

利用各种分析手段对膨润土的物理特性进行了表征 .X射线衍射分析表明钠基膨润土呈典型的六方晶胞 ,晶胞参数是 :a轴 4 .913,c轴 5 .4 0 5 ;差热分析曲线在低温区和高温区有明显的吸热峰出现 ;元素分析钠、钾离子的含量大于钙、镁离子的含量 ,在性能上表现为钠质膨润土具有较强的离子交换能力 ;显微分析表明其表面呈皱隙状 ,测定比表面积高达 2 4 .5 2m2 /g;吸水率测定表明膨胀率大 ,说明它具有密封功能 ,可有效阻滞地下水的渗入 .利用SF6示踪技术 ,通过采集不同时间段取样池样品 ,分析样品中示踪气体浓度 ,绘制取样池示踪气体浓度随时间的变化关系曲线 ,根据费克扩散定律计算扩散系数 .实验结果表明 ,随着压实膨润土密度的增大 ,示踪气体扩散系数迅速减小 ,当密度大于 1.8g/cm3 时 ,扩散系数降至 10 -9m2 /s.研究结果表明 ,膨润土性能优化是通过在膨润土中添加适量的活性炭 ,可明显改善其对气体的阻滞能力 ;增加其对放射性气体滞留能力 ;添加少量的石英砂增加其机械性能、导热性和减少蠕变性 ,将引起对气体阻滞能力的下降 .综合考虑 ,在膨润土中各添加 5 %活性炭和石英砂 ,既对气体具有较好的滞留能力 ,又具有较好的工程特性 .     

Photo-induced effect in the layered perovskite manganite La<Subscript>1.2</Subscript>Sr<Subscript>1.8</Subscript>Mn<Subscript>1.8</Subscript>Co<Subscript>0.2</Subscript>O<Subscript>7</Subscript>

It is helpful to study the photo-induced effect in the perovskite manganites not only for elucidating the mechanism of colossal magnetoresistance (CMR) effect but also for potential applications in technology. The laser-induced effect in the Co doping layered perovskite manganites La_1.2Sr_1.8Mn_1.8Co_0.2O₇, is studied in this paper and the obtained results are also compared with that gained in the Nd-doping manganites with cubic perovskite structure.     

O～3岁儿童微量元素检测及纠正150例观察与体会

对西安地区150例0～3岁儿童进行了六种微量元素：钙、锌、铜、铁、镁、硒的检测，发现微量元素缺乏可导致急慢性感染、免疫力低下、小儿营养不良、贫血、发育迟缓等症状。并对小儿营养不良、喂养不当进行矫正。其中铁、钙、锌同时缺乏占50％。     

Evolution of Spiral Waves under Modulated Electric Fields

Spirals generated from the excitable media within the Barkley model is investigated under the gradient electric fields by a numerical simulation. The spiral drift and spiral break up are observed when the amplitude of the electric fields is modulated by a constant signal or a chaotic signal. It is also verified that, even in the presence of the white noise, the whole system can reach homogeneous states after the spiral breakup, by using an adaptive strategy.     

KxCoO2·yH2O(x《0.2,y≤0.8)的晶体结构、输运及磁学性质

利用熔融KOH和Co3O4在较低温度(480℃)下反应制备出K0.36CoO2,然后用高锰酸钾溶液和饱和的过硫酸钾溶液进行氧化处理.氧化的同时伴随有水分子嵌入.K0.36CoO2用高锰酸钾和过硫酸钾溶液处理后分别得到K0.12CoO2·0.8H2O和K0.16CO2·0.6H2O.这两种化合物都属于六角晶系,表现出金属行为,脱水后主相变为正交结构并且呈现出半导体特性.K0.16CoO2·0.6H2O在56K附近可能存在自旋玻璃转变行为或其他涨落.随着钾含量的减少和水含量的增多,样品的自旋玻璃行为受到抑制或发生磁性相分离.样品K0.12CoO2·0.8H2O在零场冷却和有场冷却曲线上的分叉现象基本上消失.还讨论了产生KxCoO2与NaxCoO2体系结构和物性差别的原因.