浅析数列极限的教学

数列极限的教学,从总的策略来说,应注重对这个概念内涵的揭示和描述。极限＂ε-N＂语言应根据不同的教学对象确定不同的教授方式。另外,把描述性定义过渡成＂ε-N＂定义时应深入剖析并利于接受。     

耗散KDV型方程的渐近吸引子

摘 要:本文考虑了耗散KDV型方程 的渐近吸引子,即构造了一个有限维解序列.首先利用数学归纳法证明了该解序列不会远离方程的整体吸引子；其次，证明了它在长时间后无限趋于方程的整体吸引子, 并且给出了渐近吸引子的维数估计.     

Identification of an S5n allele in Oryza rufipogon Griff. and its effect on embryo sac fertility

Oryza rufipogon exhibits abundant genetic diversity and contains many elite genes. In this work, a total of 441 accessions of O. rufipogon were genetically examined using the functional marker S5n, revealing that 18 accessions carried the S5n allele with a heterozygous genotype (S5nS5i/j). Of these accessions, 14 were from Guangdong Province, 2 from Guangxi Zhuang Autonomous Region, 1 from Hainan Province and 1 from Jiangxi Province. Further sequence analysis spanning both sides of the deletion in S5n allel...     

渐近拟非扩张型的映像不动点的Ishikawa迭代逼近

在新的条件之下,研究了渐近拟非扩张型的映像具误差项的Ishikawa迭代逼近不动点的问题,同时给出了强收敛定理。在主要结果中,满足有界Ishikawa迭代序列{xn}的某些条件下,不需要集合K和T的值域的有界性。     

差比序列视角下“不是A但是／只是／而是B”之比较

语言中的某些词或词组可以形成一个差比序列。将不同差比序列项分别嵌入“不是A但是／只是／而是B”框架，对其嵌入条件、语义内涵和否定类别分别加以比较，可从新的视角发现这三个框架深层次的区别与联系。     

基于时间序列的灰色预测技术在估产模型中的应用

在建立估产模型过程中，引进基于时间序列的灰色预测技术，通过对样本点建立基于时间序列的灰色预测模型和常规的多元线性回归气象模型的分析比较，试图找到一种计算简单，数据要求少而精度较高，时效性较好的建模方法，为时间序列预测在农作物估产方面的应用作出一点探索。     

二元序列的广义导数

给出了序列周期的另一类定义,研究了周期二元序列的广义导数序列的周期性,得到了周期二元序列的广义导数序列的一些性质,并进一步探讨了周期分别为2N和2N-1的二元序列的广义导数。     

不定方程x3-8=65y2的解

利用同余式和递归数列的方法,证明了不定方程x3 -8=65y2无适合(x,y)=1的整数解.     

赋Orlicz范数Musielak-Orlicz序列空间中的紧局部一致凸点(英文)

给出了赋Orlicz范数Musielak-Orlicz序列空间中的紧局部一致凸点的判别准则,从而得到了赋Orlicz范数的Musielak-Orlicz序列空间是紧局部一致凸的充分必要条件。     

Ancient DNA sequences of rice from the low Yangtze reveal significant genotypic divergence

Rice (Oryza sativa) was first domesticated in the lower and middle Yangtze regions of China, and rice remains have been found in many Chinese archaeological sites. Until now, only phenotypic archeobotanical evidence, such as the spikelet bases of ancient grains, has been used to speculate on the domestication process and domestication rate of rice. In this study, we sequenced 4 genomic segments from rice remains in Tianluoshan, a site of the local Hemudu Neolithic culture in the low Yangtze and two other archaeological sites (~2400 and 1200 BC, respectively). We compared our sequences with those of the current domesticated and wild rice (O. rufipogon) populations. At least two genotypes were found in the remains from each site, suggesting a heterozygotic state of the rice seeds. One ancient genotype was not found in the current domesticated population and might have been lost. The rice remains belonged to the japonica group, and most if not all were japonica-type, suggesting that the remains might be at an early stage of indica-japonica divergence or an indica-japonica mixture. We also identified sequences with significant similarity to those from species of Sapindales, Zygophyllales, and Brassicales, which is consistent with the identification of other plant remains in the Tianluoshan site and the common rice field weeds such as mustards in southern China.