BCK-代数的几个计数定理

本文推广了文献中的有限BCK-代数子代数个数估计定理,给出了任意BCK-代数的子代数个数下界的一个估计。对于n阶BCK-代数和n阶半直接既约交换BCK-代数,本文分别给出了其子代数个数下界的较具体的表达公式。另处我们还讨论了互不同构的n阶BCK-代数的个数的下界值的估计问题。     

球形扁壳超临界变形的步进求和计算

本文用步进求和法计算了球形扁壳第二类失稳问题,在球扁壳超临界变形计算上给出了优于一级近似结果,解决了该问题无法求二级近似解的困难.算例表明步进求和法收敛于二级近似解.     

On general form of Navier-Stokes equations and implicit factored scheme

A general weak conservative form of Navier-Stokes equations expressed with respect to non-orthogonal Curvilinear coordinates and with primitive variables was obtained by using tensor analysis technique, where the contravariant and covariant velocity components were employed. Compared with the current coordinate transformation method, the established equations are concise and forthright, and they are more convenient to be used for solving problems in body-fitted curvilinear coordinate system. An implicit factored scheme for solving the equations is presented with detailed discussions in this paper. For n-dimensional flow the algorithm requires n-steps and for each step only a block tridiagonal matrix equation needs to be solved. It avoids inverting the matrix for large systems of equations and enhances the speed of arithmetic. In this study, the Beam- Warming’s implicit factored schceme is extended and developed in non-orthogonal curvilinear coordinate system.     

N-S方程组的通用形式及近似因式分解

基于张量分析,本文在任意曲线坐标系中导出了用原始变量表达的Navier-Stokes(以下简称N-S)方程组弱守恒型通用形式,其中速度采用了逆变或协变分量;与将复杂的坐标变换嵌入该方程组的流行做法相比,本文所得方程组的形式简捷、直观、更适于在贴体曲线坐标系中直接求解.文中详细讨论了这个方程的因式分解过程即将一个n维流动化为n步一维问题来求解,每一步只需解一个块三对角矩阵,从而避开了大型矩阵求逆,提高了解题速度,进一步推广和发展了Beam-Warming的因式分解法.     

几种光学图象相位加密方法的比较

本文分析比较了多种实现光学图象相位加密的方法,发现不同方法获得的加密图象有不同类型的噪音分布.无论加密相位是随机相位模板、浑沌序列的相位列阵,还是用相位重构迭代算法计算的结果,它们都能起到加密图象的功能.解密图象的质量或被相关识别的能力与解密过程中所使用正确解密相位的不同部分以及高低频分量多少有关,且其依赖程度是由不同的加密方法自身决定.     

Cu、Zn-SOD酶模型化合物催化O-2歧化作用的研究

本文采用ＮＢＴ法,利用７２１分光光度计,在ｐＨ＝７．８的条件下,测定了前文所合成的含Ｎ、Ｏ的Ｓ的Ｓｃｈｉｆｆ碱及其铜（Ⅱ）、锌（Ⅱ）配合物催化Ｏ２＾－歧化的活性,并探讨了平均抑制率与浓度的关系。     

FeO4^2—与ClO^—共存体系的氧化还原滴定分析法

在重铬酸钾容量法测Ｆｅ＾２＋和硫酸亚铁铵容量法测Ｃｒ（Ⅳ）的基础上,提出ＦｅＯ４＾２－与ＣｌＯ＾－共存体系的氧化还原滴定分析法。该方法实用、可靠、对样品分析,结果令人满意。     

负载型La0.8Sr0.2MnO3燃烧催化剂的载体效应

Combustion catalysts La0.8Sr0.2MnO3 supported on γ-Al2O3, α-Al2O3, cordierite (2MgO•2Al2O3•5SiO2) and ZrO2 were compared. Further investigation was focused on LSM/ γ-Al2O3 catalyst. It was observed that LSM/γ－Al2O3 catalyst loaded with 20% (mass fraction) LSM (La0.8Sr0.2MnO3 or corresponding oxides), heated at 750℃ or above, perovskite-type oxides were found by XRD examination, whereas, the same catalyst loaded with 10% or less LSM, perovskite oxides were absent, calcination temperature about 750℃ is necessary for the formation of perovskite structure in LSM/γ-Al2O3 catalysts. High activity of complete oxidation of xylen will be obtained when perovskite-type oxides.
Investigation of TPR showed that neat LSM or LSM/γ-Al2O3(20%) was reduced by H2-N2 mixed gas. Two degradation processes took place. In the first, reduced temperature peak was about 350 - 450℃. If reduction ended at 400℃, perovskite structure was retained, which may be due to the reduction of Mn3+to Mn2+ on the surface of LSM only. In the second process, perovskite structure was destroied, and La2O3, Mn2O3, Mn - Sr - O oxides could be obtained, which took place in the temperature range 685 - 750℃ and ended at 800℃. This was proved by TPR experiments (Fig. 3, 5) and XRD patterns (Fig. 4)
Catalysts LSM/γ-Al2O3(10% or 20%) heated at 500℃ have only one TPR peak, i. e. lower temperature peak. This is due to the absence of perovskite-type oxides in the catalysts. However, neat LSM or LSM/γ-Al2O3(20%) heated 750℃ or above, not only the first low temperature TPR peak but also the second peak, which is contributed by the perovskite-type oxides in these catalysts appeared. Therefore, the second TPR peak, i. e. the higher temperatue peak is a characteristic peak for perovskite-type oxides in the reduced process. When LSM/ γ-Al2O3 (10%) catalys is heated at 750℃, no perovskite-type oxides were detected by XRD, and the second reduction peak was absent also in TPR process. \
The order of the second reduction peak temperature(characteristic peak of perovskite - type ox- ides) is: neat LSM(750℃）> LSM/γ-Al2O3 20% (685-698℃) -deposited LSM/γ-Al2O3 (698℃) > LSM/γ-Al2O3 15% (677 - 680℃) >(LSM/γ-AL2O3 10% 620 - 630℃, for Mn - Al - O medium oxides on surface). It is correleted with the increasing of the effect of support sequentially.
When LSM/γ-Al2O3 catalysts were heated at 900℃, more stable phase, spinel MnAl2O4 appeared, which could be proved by TPR of model catalyst MnAl2O4/γ-Al2O3.     

基于KFCM增量更新的无线电引信目标识别方法

针对传统无线电引信在复杂电磁环境下作用效果较差的问题,以连续波多普勒引信为例,通过对引信检波输出信号频域的分析,提出一种基于熵的特征提取方法,并利用KFCM算法对信号进行分类识别。由于实际战场环境复杂且不可预测,其背景噪声强度与实验环境下存在差异,因此结合KFCM增量更新特性,使分类模型根据噪声强度变化而实时更新调整,从而达到更好的分类效果。实验结果证明,基于增量更新KFCM算法能显著提高不同信噪比下引信目标识别能力,将KFCM增量更新算法运用到无线电引信抗干扰能取得良好效果。     

修正相场晶体(MPFC)模型的二阶无条件能量稳定数值格式

本文研究修正的相场晶体(MPFC)方程的二阶无条件能量稳定数值格式.首先,利用标量辅助变量(SAV)法和二阶向后欧拉(BDF2)公式,得到了一个数值格式;其次,给出了能量耗散定律,严格证明了该数值格式是质量守恒的,唯一可解的,无条件能量稳定的;最后,通过数值实例验证了格式的精度和稳定性.