晶粒尺寸和热处理对Sm2Fe17N3/Fe3N/BN软磁/硬磁复合材料的合成及磁性能影响

采用高能球磨和真空热处理方法制备Sm2Fe17N3/Fe3N/BN复合材料, 并研究球磨过程中晶粒尺寸变化对固态相变和磁性能的影响.  结果表明: Sm2Fe17N3和Fe3N相产生的条件是Fe的晶粒尺寸达到纳米量级（D＜80 nm）并形成Fe(Sm)固溶体; 随着退火时间的增加, 300 ℃真空退火的球磨样品中Sm2Fe17N3的结晶物增多, 矫顽力提高, 表明样品的磁性能与Sm2Fe17N3的结晶程度有关.     

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。     

N,N-二正丁基二硫代氨基甲酸锑的合成与表征

应用一步法合成配合物N,N-二正丁基二硫代氨基甲酸锑(SDBC).通过IR、13C-NMR、元素分析EA和等离子发射光谱ICP等对产物的分子结构进行表征.表征结果显示合成产物符合目标物SDBC的组成与结构,其配位数n=3;DSC测定SDBC的熔点为73℃,熔程较短,纯度较高;TGA表明SDBC有较好的热稳定性,当温度高于220℃时,它有个明显的热失重区域.     

First clear case of carnivory in marine Copepoda Harpacticoida

Males and females of Ectinosoma carnivora sp. n. from Andros, Bahamas are described. The new species is closely related to E. melaniceps Boeck, 1865 and E. pectinatum Mielke, 1979. A specialized regular slit-shaped glandular pore is described and named the U-pore. Scanning electron microscopy revealed a net of filaments that may cover the whole body of E. carnivora sp. n. It consists of mucus emerging from U-pores. Video investigations show E. carnivora sp. n. and E. melaniceps to be highly mobile and to travel with great velocity in, on and outside the sediment. They exhibit a mode of feeding unreported so far for marine harpacticoid copepods. As observed in laboratory cultures these species are carnivorous and feed on fresh dead ostracods but also on fresh fish meat. When exposed to such food they change their linear movement to what is described here as a helical approach to the food source until contact is established and feeding begins. Carnivory and the ability to locate food sources quickly are believed to be more widespread within the Ectinosomatidae Sars, 1903 and probably are the reason for the great diversity of this family in many different environments.     

几种新空间类的性质及其相互间的关系

本文引入了０仿紧、０仿紧及强仿紧的概念．讨论了他们的性质及它们与其它空间类的关系．     

模型N=∪{L[A]:AìO_n可数}中的大基数

在文献[2]中,C.Sureson定义并研究了模型N.本文证明了下面结论:假设NZF,则(i) 如果又是弱紧基数,那么它在N中也是弱紧的.(ii) 如果λ是难形容的,那么它在N中也是难形容的.(iii) 如果V=N,则不存在可测基数.     

二阶线性中立型微分差分方程非振动解的类型与判别

本文讨论了二阶线性中立型微分差分方程d~2/dt~2[x(t)-cx(t-τ)]+px(t-σ)=0的非振动解的所有类型及其判别。     

扰动线性差分方程解的有界性

本文在已讨论的扰动线性差分方程解的渐近性的基础上,进一步研究了解的有界性,得到了一些前所来有的结果.