多环芳香硫化合物的定量结构-气相色谱保留指数关系

应用分子电性距离矢量(MEDV)对114个多环芳香硫化合物(PASHs)进行结构表征,通过多元线性回归建立了PASHs的气相色谱保留指数与MEDV参数之间的定量结构-保留值关系模型;同时采用逐步回归分析进行变量筛选,继而以留一法交互检验对所得优化模型进行预测能力评价,所建立的模型的相关系数为0.9947,交互检验相关系数为0.9940,表明该优化模型具有良好的稳定性和预测能力。此外,通过将样本集按2:1分成校准集和测试集预测,统计分析结果显示所建的模型具有良好的相关性和稳定性。本文所建的定量结构-保留值关系(QSRR)模型为预测PASHs的气相色谱保留指数提供了一个便捷有效的新方法。     

月亮走,我也走——对一道关于动圆中考题的思考

笔者有幸参与了2011年嵊州市中考数学的阅卷工作,对绍兴市数学中考试卷中的第16题感触颇深,以下是笔者对该题的分析、反思,以供同行参考.     

运用Poincaré-Miranda定理数值验证变分不等式解的存在性

本文运用Poincaré-Miranda定理数值验证变分不等式问题解的存在性. 证明这一新方法相对于已有的方法更具有普遍性, 并通过数值例子说明本方法的高效性.     

一种软包装超级电容器及其高电压模块

超级电容器是一种介于电池与传统电容器之间的新型储能器件,具有高能量密度、高功率密度的双重特性[1].超级电容器可以配合燃料电池、锂离子电池作为电源系统,解决电动汽车在加速、爬破、刹车时单一电池无法克服的问题;超级电容器也可以作为太阳能、风能等绿色发电系统储能装置;它亦可以作为电子、通讯、医疗等设备的主力电源.     

Hadamard乘积矩阵的一些性质

本文给出了Ｈａｄａｍａｒｄ乘积矩阵的秩和行列式的两个不等式     

溶胶-凝胶法BazTiSi2O8铁电薄膜的制备及结构表征

采用溶胶-凝胶工艺在Si(100)衬底上制备了Ba2TiSi2O8(BTS)薄膜。通过XRD衍射、傅立叶红外(FT-IR)、拉曼(Raman)散射光谱和原子力显微镜(AFM)对薄膜的显微结构进行了表征。AFM分析显示，BTS薄膜表面光滑，晶粒尺寸在0．30～0．50μm。薄膜结构分析表明：随着退火温度的增加，BTS薄膜的结晶度增加，薄膜结构变得更加致密。同时，随着退火温度的升高，晶胞尺寸出现了收缩，导致了BTS薄膜的四方比c／a从0．613上升到0．618，将对薄膜的压电性能产生影响。     

火焰原子吸收法测定霞石中的氧化钾和氧化钠

本方法用于测定霞石中的钾、钠，主要通过在溶样时加入氢氟酸除去二氧化硅，调整溶液中钾、钠的含量，消除互相之间的干扰，加入氯化铯消除电离因素的干扰，提高了分析结果的准确性和重现性，使测定结果更接近化学分析值。回收率为99．2％-101．6％，总体标准偏差为0．04％。     

NETS IN MULTISYSTEMS OF n 3 AND n 4 PHASES

From the free energy surfaces in G-p-T space a series of basic characteristics have beensummarized. For the reactions of most systems with phases of constant composition, eachof the surfaces should be approximate to a plane. After they meet, the points, curves andsurfaces possess distinct stability levels. Across the intersecting curves and points, the freeenergy surfaces and curves will change their stability levels. Linking invariant points ofdistinct stability levels, we can get various univariant curves differing in structure. Theangular extent between two univariant curves around the invariant points is less than 180°.The surfaces meeting in space and projecting onto the p-T section will give rise to partiallyclosed or open, rather than completely closed nets. Finally, based upon the basic characteristicsand criteria, we have derived the partially closed nets of n 3 and n 4 phases with maxi-mum closure by using geometrical and analytical methods. From the free energy surfaces in G-p-T space a series of basic characteristics have beensummarized. For the reactions of most systems with phases of constant composition, eachof the surfaces should be approximate to a plane. After they meet, the points, curves andsurfaces possess distinct stability levels. Across the intersecting curves and points, the freeenergy surfaces and curves will change their stability levels. Linking invariant points ofdistinct stability levels, we can get various univariant curves differing in structure. Theangular extent between two univariant curves around the invariant points is less than 180°.The surfaces meeting in space and projecting onto the p-T section will give rise to partiallyclosed or open, rather than completely closed nets. Finally, based upon the basic characteristicsand criteria, we have derived the partially closed nets of n 3 and n 4 phases with maxi-mum closure by using geometrical and analytical methods.     

牛顿与二阶拟牛顿混合迭代方法

这里F:R~n→R~n是充分光滑的向量函数。用逐步迭代法求解(1.1)的主要方法有牛顿法或拟牛顿法。用二步或多步混合迭代方法求解(1.1),这种方法以前未曾见过。 1984年Pan提出二阶拟牛顿法,我们用1981年More,Garbow and Hillstrom提出的非线性方程组的测试函数对二阶拟牛顿方法进行测试,发现二阶拟牛顿法对于初始点及初始近似Jacobi阵的反应非常灵敏,若用牛顿法与二阶拟牛顿方法交替使用,其迭代过程所