基于互联网的常微分方程数值解法的可视化设计

利用Microsoft Visual J＋＋6.0作为实验开发平台,采用Java语言及Applet嵌入网页技术,选择预估-校正法、龙格-库塔相结合的数值算法,实现了基于互联网的常微分方程数值解法的可视化,并通过实例演示该实验设计的各功能,包括用户对相关原理学习、数据的录入、修改、函数识别、常微分方程的求解、绘图及打印等.     

推广的θ型Calderon-Zygmund核多线性奇异积分算子在原子空间上的有界性

燕敦验研究了广义Calderon-Zygmund核的多线振荡形奇异积分算子的LP有界性.受这些文献的启发,本文研究了推广的θ型Calderon-Zygmund核的多线性奇异积分算子,证明了它是从H1(Rn)到L1(Rn)有界的.     

对称性在二重积分计算中的应用研究

在二重积分计算中,利用积分区域的对称性和被积函数的奇偶性,简化积分运算,并通过典型例题说明之。     

广义变系数Kadomtsev-Petviashvili方程的孤立子解

讨论了广义变系数Kadomtsev-Petviashvili方程.首先假设存在孤波解的形式,然后利用符号计算求得其孤立子解.     

求一类Riccati微分方程通解的分项组合法

讨论了一类Riccati微分方程的通解,得到了它可以使用分项组合法的充要条件,为寻求Riccati微分方程的通解提供了有效的方法,并给出了它的应用.     

钓鱼岛争端问题的不同解决方案比较分析

钓鱼岛自古以来就是属于中国的固有领土,但由于种种原因,现在被日本所控制。钓鱼岛争端问题不仅成为长期以来横亘在中日之间的巨大障碍,而且愈来愈发展成恶化两国关系、引发两国局势高度紧张的火种。解决钓鱼岛争端问题有哪些不同的方案和思路？对中国而言,哪些方案最有利、最可行？笔者拟对以下五种方案优劣成败进行比较分析。     

等价无穷小代换求极限的方法推广

由于教学的需要,对利用等价无穷小代换求函数极限的方法作了进一步的推广,所得主要结论,在很容易验证的条件下,将无穷小代换的方法推广到多个复合函数无穷小代数和之比及幂指函数和含变上限积分函数的情况,扩大了等价无穷小代换使用的范围。     

A novel way of liver preservation improves rat liver viability upon reperfusion

Background/aim： Currently, the liver is cold-preserved at 0-4 ℃ for experimental and clinical purposes. Here, we investigated whether milder hypothermia during the initial phase of the preservation period was beneficial for liver viability upon reperfusion. Methods： In the first set of experiments, rat livers were preserved either conventionally in clinically used histidine-trypthopan-ketoglutarate （HTK） solution （Group A： 45 min and Group B： 24 h） or by slow cooling HTK solution （from 13 ℃ to 3 ℃） during the initial 45 min of preservation （Group C： 24 h）. In the second set of experiments, additional groups of livers were evaluated： Group BB-preservation according to Group B and Group CC-preservation according to Group C. Further, some livers were preserved at 13 ℃ for 24 h. Livers were then reperfused using a blood-free perfusion model. Results： Bile production was approximately 2-fold greater in Group C compared to Group B. Alanine transaminase （ALT） and aspartate transaminase （AST） release into perfusate were 2-3-fold higher in Group B compared to Group C. No significant differences were found in ALT and AST release between Group C and Group A. Livers in Group CC compared to Group BB exhibited significantly lower portal resistance, greater oxygen consumption and bromosulfophthalein excretion into bile and lower lactate dehydrogenase （LDH） release into perfusate. Histological evaluation of tissue sections in Group BB showed parenchymal dystrophy of hepatocytes, while dystrophy ofhepatocytes was absent in Group CC. Livers preserved at 13 ℃ for 24 h exhibited severe ischemic injury Conclusion： These results suggest that the conventional way of liver preservation is not suitable at least for rat livers and that slow cooling of HTK solution during the initial phase of cold storage can improve liver viability during reperfusion.     

中国共产党解决民生问题的历史经验

中国共产党高度关注民生、注重解决民生问题,积累了丰富的历史经验,主要有:解决民生问题的根本保证是坚持党的领导,基础是发达的生产力,主体是人民群众,根本方法是统筹兼顾,基本目标是公平正义,出发点和落脚点是人民群众的根本利益,重要保障是制度建设。     

Banach空间中一类反向混合单调算子方程的迭代解法

运用半序理论与单调迭代技巧,讨论了一类反向混合单调算子方程A(x,x)=Bx解的存在唯一性,并给出了迭代序列收敛速度的误差估计,所得结果是某些已有结果的本质改进和推广.