磁存储硬盘表面全氟聚醚衍生物润滑膜的X射线光电子能谱研究

利用ＸＰＳ分析了计算机硬盘表面全氟聚醚衍生物润滑膜的结构。结果表明,根据ＸＰＳ谱图中的Ｃ１５峰位可以分辩润滑剂化学结构式中各官能团;根据硬盘衬底的Ｃ－Ｏ基ＰＦＰＥ的Ｆ－Ｏ基团的Ｏ１５峰强之比可以确定硬盘表面润滑膜的厚度,因工艺条件不同,膜厚处在１．５～６．０ｎｍ范围之间。     

底为正方形的三维装箱问题

本文讨论如何将一堆底部为正方形 ,长、宽、高均不超过 1的盒子装入一底为 1× 1,高为正无穷的柱形箱子 ,使装箱高度 Z为最小的问题 .该问题已知为 N P难的问题 . Li和 Cheng在 1990年提出了多项式近似算法 C1,其渐近性能比 r( C1) = 2. 687 5(见参考文献 [1 ]) . 本文根据算法 C1的思想 ,进一步利用盒 子底部为正方形的特点 ,尽可能不浪费高度空间 ,提出了所谓“单元装箱法” D,使新算法的渐近性能比得到改进: r (D ) ≤ 2*251/78 4= 2. 3 201 5.     

Crystallization and melting behavior of the soft and hard segments in poly(ester-ether)s. I. Ethylene oxide-ethylene terephthalate segmented copolymers

The crystallization and melting behavior of a series of ethylene oxide-ethylene terephthalate (EOET) segmented copolymers with different soft segment molecular weight and hard segment weight content were studied by differential scanning calorimeter (DSC) and polarized microscope. The crystallizability of both the hard and the soft segments became worse than that of the corresponding homopolymers due to the interactions of the different segments. The crystallizability of the soft segments is mainly determined by the soft segment molecular weight, but is affected greatly by the content and the crystallinity of the hard segments. Conversely, the soft segment length and content also have a great effect on the crystallization of the hard segments. However, the melting points of the hard segments are determined by the average hard segment length. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2918–2927, 1999     

A nanoscopic view of structure and deformation of hard elastic polypropylene with scanning force microscopy

Scanning force microscopy (SFM) was used to visualize the surface of hard elastic polypropylene (HEPP) film. The surface morphology of unstrained HEPP shows crystalline and noncrystalline rows oriented parallel to the extrusion direction. The crystalline rows are composed of lamellar blocks. The dimensions of crystalline and noncrystalline regions are determined. The structural surface changes induced by stepwise elongation of the film with a home-built stretching device are documented by SFM. Stretching of HEPP perpendicular to the extrusion direction causes cracks advancing through several crystalline rows. During elongation parallel to the extrusion direction the separation of adjacent lamellae by their translatory displacement occurs. Deformation-induced structural changes of HEPP on the nanometer scale are compared with proposed deformation models. Nanostructural changes are correlated with characteristic variations in the force-elongation curve. © 1996 John Wiley & Sons, Inc.