Effect of high temperature alkali cooking on the constituents,structure and thermal degradation of hemp fiber

Degumming of hemp fiber by high temperature alkali cooking was investigated, and the effect of temperature and dosage of alkali on the constituents, structure, and thermal degradation of hemp fiber was also discussed in this work. The morphology, structure, and thermal degradation of hemp fiber after high temperature cooking were investigated through SEM, FTIR, WAXD, and TG analysis. The results indicated that the high temperature cooking process was effective for removing hemicelluloses and lignin and could also improve the thermal stability of cellulose. Crystallinity index of the treated hemp fiber was increased, which was related to the cooking temperature and NaOH dosage. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Structure and processability of iodinated poly(vinyl alcohol). IV. Drawability of the films iodinated at solution before casting

The drawability of iodinated at solution before casting (IBC) polyvinyl alcohol films prepared by casting aqueous solutions of 10 wt % PVA containing 15.2, 39.8, 83.2, 117.0, and 140.1% was examined with a tensile tester at 20–60°C. The tensile behavior of IBC films showed that the yield and breaking loads were much lower, and the breaking elongation was even higher than those of the unoriented iodinated after casting (IAC) films as well as the untreated PVA films. The maximum draw ratios of the films with the weight gain of 15.2, 39.8, 83.2, 117, and 140.1% were 4.5, 5.5, 8.5, 8.0, and 7.5, respectively, which were achieved at 20°C in all. The crystallinity of all films increased by the maximum draw, regardless of crystallinity before drawing. The crystalline structure was recovered to the original PVA crystalline lattice by deiodination. Amorphous orientation and initial moduli increased with the maximum draw ratio, while the orientation of crystals was constant. The orientation and moduli increased up to the weight gain of 83.2%, whose highest draw ratio and initial modulus were 8.5 and of 7.1 GPa, respectively, and then decreased. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

A study on dynamic friction of different spun yarns

This article presents the results from a study of yarn-to-yarn (YY) and yarn-to-metal (YM) frictions conducted on ring, rotor, air-jet, and open-end friction (OE friction) spun yarns at different relative speeds and input tensions. The results indicate that the behavior of frictions for YY is different than that of YM. In case of YY friction, OE friction yarn shows maximum friction followed by rotor, air-jet, and ring spun yarns; however, a reverse order is noticed for YM friction. The relative speed and input tension have significant influence on the frictional behavior of spun yarns. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polymer transcrystallinity induced by carbon nanotubes

In this work, we provide the evidence of polymer transcrystallinity in the presence of carbon nanotubes (CNTs). The interfacial morphology of carbon nanotube fiber-polypropylene matrix is investigated by means of polarized optical microscopy (POM), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The supramolecular microstructures of polypropylene transcrystals induced by the nanotube fiber are observed in the range of isothermal crystallization temperatures from 118 °C to 132 °C. The dynamic process of transcrystallization is analyzed by using the theory of heterogeneous nucleation. Microstructure analysis shows that the nanotubes can nucleate the growth of both α- and γ-transcrystal, and α-transcrystals dominate the overall interfacial morphology. Close to the nanotube fiber surface, a cross-hatched lamellar microstructure composed of mother lamellae and daughter lamellae is observed.     

组成对MgO-ZrO2-CaO系合成料结构与性能的影响

以脱硅锆、轻烧氧化镁、消石灰为原料，进行了MgO-ZrO2-CaO系原料的合成，研究了化学组成(包括ZrO2含量、CaO／ZrO2比)，烧成温度，杂质等对合成料性能和组织结构的影响。     

影响带锯机锯切质量的原因及处理措施

通过对锯切装置的改进，提高了锯切性能，降低了锯条成本，保证了锯切质量，使设备更加高效、安全的工作。     

电子工业用高纯氮的生产

生产电子工业用高纯氮的制氮装置 ,其要点和难点是一氧化碳和氢的清除。采用一氧化碳转换炉和特殊的冷箱内流程组织 ,可以生产纯度为 99 9999%以上的高纯氮。对制取电子工业用高纯氮制氮装置与常规制氮装置加氮终端净化器两种流程进行了比较。     

乙烯裂解炉对流段局部结构设计改进

介绍了乙烯裂解炉对流段的结构功能,各部件局部结构的改善设计。     

虚拟企业模型并行仿真研究

随着各种全新的制造理念,特别是虚拟企业的出现,企业模型的规模不断扩大,使目前存在的大多数企业模型仿真系统的效率大大下降。该文针对此问题,通过深入分析虚拟企业模型结构,并在已有的构件化企业建模体系CEMS及其仿真系统的基础上,结合异步仿真技术和多线程技术提出了一种分层式企业模型仿真体系结构,为虚拟企业模型的快速高效的仿真提供了一种有效的方法。