Surface properties of surfactants derived from natural products. Part 1: Syntheses and structure/property relationships—Solubility and emulsification

Several novel and some previously known, mostly sugar-based, surfactants have been synthesized and some of their surface properties have been characterized and compared with those of commercial nonylphenol ethoxylates. The surfactant solubility in water, ethanol, and dodecane was studied. The properties of these compounds as emulsification agents in systems composed of the surfactant with water/isopropyl myristate, water/rapeseed oil, and water/dodecane are presented. The aqueous solubility of the surfactants follows the general trend expected from their hydrophilic-lipophilic balance according to Griffin (HLBG), but it is also clear that the nature of the headgroup and the structure of the nonpolar part affect the solubility in a manner not aptured in the standard HLBG concept. An ester or amine group as the connecting unit between the hydrophile and the hydrophobe produces a more water-soluble surfactant than the corresponding amide derivative. Some effective emulsifiers were found. For instance, the surfactants with a dehydroabietic nonpolar group appear to be promosing emulsifiers. Most sugar-based surfactants were able to form macroemulsions of up to around 2 wt/vol% of oil. The stability of many of these amulsions was very high, extending for months.     

Effect of Vortex Restructuring on Heat Transfer in an “Inverted” Flame

The papers deals with formation of vortex structures during combustion of a fuel gas–air mixture injected vertically down through a hole in a flat plate. It has been established that the shape, position, and number of vortex cells are determined by the flow rate and composition of the fuel mixture. It is shown that as the flow rate increases from the minimum critical value for which a vortex structure arises, the number of vortex cells decreases from five or six to one. A further increase in the gas flow rate leads to transition to turbulence of the combustion product flow. The presence of a vortex structure increases the critical Reynolds number at which the flow becomes turbulent. Reverse transition to the structure with an increased number of vortex cells occurs with a delay in the gas flow rate (gas discharge hysteresis). Variation in flow rate is accompanied by bifurcation of the number of vortex cells.     

Composites based on eucalyptus tar pitch/castor oil polyurethane and short sisal fibers

Polymeric materials are being developed with renewable resources to promote industrial progress with environmentally friendly technologies. For this reason, polyurethane samples were prepared with 4,4′‐diphenylmethane diisocyanate (NCO/OH = 1), eucalyptus tar pitch (biopitch), castor oil as a polyol, and dibutyltin dilaurate as a catalyst. These materials were reinforced with different contents of short sisal fibers (0, 2.5, 5.0, 7.5, and 10.0%) and were prepared by resin‐transfer molding. The composites were characterized by IR absorption spectroscopy, thermal analysis (thermogravimetry and differential scanning calorimetry), impact resistance, scanning electron microscopy, and water absorption resistance. These materials showed hydrophobic characteristics, despite the addition of sisal fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3797–3802, 2003     

界面改性PA6/TPE共混物的形态结构与性能

通过控制马来酸酐(MAH)的用量制得不同接枝率的马来酸酐接枝热塑性弹性体(TPE-g-MAH),利用其与尼龙6(PA6)在共混过程中的反应增容作用,实现了与PA6的相容共混,并研究了PA6/TPE共混物的结构与性能。结果表明,TPE-g-MAH可有效地提高PA6/TPE共混物的韧性,且随着其接枝率的增加,共混物的韧性提高;TPE-g-MAH有效地改善了PA6/TPE共混物的界面相容性,并且随着其含量的增加,相界面增容效果变好。     

Impact of “Super Acid” like filler on the properties of a PEGDME/LiClO4 system

Composite polymer electrolyte based on a new class of filler added to a PEGDME/LiClO₄ model system has been investigated. “Ceramic super acids” used consist of grafted SO₄²⁻ groups on Al₂O₃ particles surface obtained by calcinations route. Conductivity, DSC and FT-IR measurements performed on such composite electrolytes, when compared to the model PEGDME/LiClO₄ electrolyte, showed only slight improvement of their inner characteristics. In contrary, Li/Li symmetric cells study, by means of impedance spectroscopy, has presented a spectacular decrease of the interfacial resistance compare to the model electrolyte. This result opens a new pathway of investigation to master the lithium metal/polymer electrolyte interface.     

可伸缩铰支管接头简介

本文指出了埋入地下的刚性管接头连接的管道易出现的问题及为解决这些问题而发明的可伸缩铰支管接头的特点及结构。     

固体推进剂燃烧机理诊断方法的研究进展

介绍和评述了诊断含能材料热分解和推进剂燃烧波结构的方法、仪器和研究进展,以及含能材料和推进剂热分解和燃烧波结构的研究结果,探讨了燃烧机理研究方法的发展方向。提出需要不断完善和更新推进剂燃烧的诊断方法,以获得更为全面的接近真实条件下推进剂燃烧的有效信息。附参考文献14篇。     

黄原胶的结构、性能与应用

简要介绍了黄原胶的结构、性能;综述了它在化学工业及食品工业中的应用;重点论述了黄原胶作为悬浮剂、乳化剂、稳定剂、增稠剂等在日用化学工业中的应用,具有优良的悬浮性、乳化性、流变性、热稳定性及酸、碱稳定性;最后指出了我国在黄原胶应用方面的不足及以后的发展方向。     

磁性漆酚缩甲醛微球的制备与表征

在共沉淀法合成磁流体的基础上,用悬浮缩聚法制备了磁性漆酚缩甲醛微球,并用X射线粉末衍射、透射电镜和热重分析等对微球进行结构表征。实验结果表明,Fe3O4磁流体的粒径为纳米量级,纳米Fe3O4粒子能够提高复合物的热性能。该微球粒径约1mm,是核壳结构,具有良好的耐溶剂性和耐热性。     

The Cerebellum according to the Ouroboros Model,the ＂Interpolator Hypothesis＂

The Ouroboros Model offers a novel cognitive architecture with an algorithmic backbone of iterative and self-referential processing. All memory content is organized into meaningful pieces of data, i.e.,chunks and schemata, which are laid down as a kind of snapshots of all activations at a relevant point in time. This entails a grainy structure of memory content. Whereas a core process of ＂consumption＂ analysis can naturally be defined taking advantage of this parcellation, it necessitates interpolation for fine nuances, especially for the representation of intermediate values during transients. It is argued that, in the vertebrate brain, essential interpolation functionality is provided by the cerebellum. Findings concerning movement control and perception as well as the involvement of the cerebellum in more abstract, cognitive, tasks can be interpreted as reflecting a function of the cerebellum as a co-processor, i.e., a general-purpose interpolator. The cerebellum is thus boosting representations in cerebral cortex areas, which are reciprocally connected with cerebellar cortex areas. In this paper, it is sketched how the new ＂interpolator hypothesis＂ can explain manifold observations, effectively subsuming previous theories of the function of the cerebellum. Directly relating to the BICA challenge, a general-purpose interpolator is postulated as an efficient device providing fine-grained resolution for the representation of diverse content, potentially useful in any cognitive architecture.