Thermoplastic extrusion—the mechanism of the formation of extrudate structure and properties

Systems processed by thermoplastic extrusion can be regarded as heterophase polymer melts of incompatible water-plasticized biopolymers. In the process of thermoplastic extrusion, proteins and polysaccharides are melted at high pressure and temperature below the temperature region of their thermal decomposition. Dispersed particles of these systems can be deformed in flow. The mixed-melt anisotropic structure, formed in flow, is fixed by rapid conversion of the melt jet that lets the extruder die from a viscous state to a rubber-like state and then to a glassy state caused by cooling and drying. Incompatibility of proteins and polysaccharides in their water-plasticized melt mixtures impacts on structure formation and texturization during thermoplastic extrusion. Presented at the 20th ISF World Congress and 83rd AOCS Annual Meeting and Expo, May 10–14, 1992, Toronto, Ontario, Canada.     

多元统计分析在矿井水淡化处理中的应用

主要介绍多元统计分析方法,即利用主成分分析与因子分析方法,对微有机污染矿井水淡化前处理工艺进行分析,得到影响矿井水乳化油去除的主要因素。此方法对决策者有一定的参考价值。     

LOCAN 320声发射仪数据格式识别与转化系统的开发

在简介LOCAN 320声发射仪和HP VEE可视化编程语言的基础上,介绍了LOCAN320数据格式识别与转化系统的开发。该转化系统与LOCAN 320 自带软件的处理结果相比,增加了数据处理的功能和灵活性。     

基于NSGA-II 的具有多目标子学科的协同优化方法

针对子学科具有物理目标的多目标协同优化问题, 研究基于NSGA-II 的求解策略. 鉴于子学科个体满足约束可行性的进化过程与系统级分配期望值无关, 提出具有良好的可行性和多样性的初始种群生成方法, 以提高多目标子学科的计算效率和计算精度. 为了解决由一致性目标函数与物理目标函数的作用不同而造成的NSGA-II 非支配级排序困难, 提出将子学科一致性目标函数转化为子学科自身约束的策略. 最后, 利用工程算例对所提出方法的有效性进行了验证.

     

任务栏通知区应用程序的设计

介绍了 Windows任务栏通知区的基本数据结构及其相关 API函数 ,讨论了在 Delphi下任务栏通知区应用程序的设计方法。     

Wolbachia induces costs to life-history and reproductive traits in the moth,Ephestia kuehniella

The intracellular endosymbiont Wolbachia pipientisis is well-known as one of the most common bacterial symbionts of arthropods. Recently, research has focused on the potential to utilize Wolbachia as a biocontrol agent of agricultural and medical pest insect species. Wolbachia blocks host infection from other pathogens and viruses in some species, however, it can also influence host life-history and reproductive traits. Therefore, in order to understand the biological impact and potential economic utility of Wolbachia, it is necessary to investigate the effects of Wolbachia infection on host traits. We compared life-history and reproductive traits between Wolbachia-infected and cured population in Mediterranean Flour Moth, Ephestia kuehniella. E. kuehniella is well known as a pest of stored products, and when infected with Wolbachia, it exhibits cytoplasmic incompatibility between uninfected females and infected males. We found that E. kuehniella suffers costs as a result of Wolbachia infection, through decreased larval survival and adult longevity, and prolonged developmental period. Moreover, reproductive performance was greater in the uninfected population, when excluding the effect of cytoplasmic incompatibility. Our results indicate that E. kuehniella suffers deleterious effects on both life-history and reproductive traits as a result of being infected with Wolbachia. We suggest such costs should be considered when evaluating the efficacy of utilizing Wolbachia in pest control.     

Microstructure and elastic modulus of mixed gels of gelatin + oxidized starch: Effect of pH

The microstructure and elastic shear modulus of cold-set gels formed from high-sugar aqueous mixtures of gelatin (7 wt%) + oxidized starch (0-6 wt%) were investigated as a function of pH. Samples prepared at 90 °C, with citric acid added to adjust the pH, were rapidly quenched to ∼1 °C, subjected to a standard thermal treatment (40 °C for 10 min), and then investigated by confocal microscopy and small-deformation rheology at 24 °C. Under ‘natural’ conditions of pH ≈ 5.2 (no citric acid addition), the samples exhibited phase separation with a characteristic spinodal-type morphology. The spatial extent of the structural heterogeneity, expressed by a single length-scale parameter, was found to increase with starch concentration. Gradual acidification led to a reduction in this length-scale parameter, leading to complete inhibition of phase separation below a certain characteristic pH value in the range 4.5-4.9 (depending on starch content). Over the investigated pH range, the effect of starch addition was to reduce the storage modulus of the resulting gel. This reduction was more pronounced for the phase-separated samples. The pH of maximum rigidity was found to decrease from pH_max ≈ 4.6 for 0 wt% starch to pH_max ≈ 4.2 for 6 wt% starch. Taken all together, these observations can be understood in terms of the effects of pH on the cross-linking behaviour of the gelatin and the nature of the gelatin-starch electrostatic interactions. The microscopy results are consistent with a transition in behaviour from thermodynamic incompatibility (segregative interactions) at high pH to soluble complexation (associative interactions) at low pH.     

遗传算法在航天器轨迹优化中的应用

介绍了国内外遗传算法在航天器轨迹优化应用中的发展现状,指出了直接法和间接法的不足.分析了遗传算法求解航天器轨迹优化问题中的参数化方法、约束处理和遗传搜索策略等关键问题,介绍了作者在这些方面的一些研究成果.阐述了多目标遗传算法在轨迹优化方面的需求和应用,指出了一些不足并提出了几个值得进一步探讨的问题.研究表明以遗传算法为核心的航天器轨迹优化设计方法正在发展成为不同于直接方法和间接方法的智能优化设计方法.     

粗集理论中不相容规则的一种修正算法

粗集理论是继概率论、模糊集、证据理论之后的又一种处理模糊和不确定性知识的数学工具。针对粗集理论在实际应用中常常出现的条件属性相同而决策属性不一致问题,提出了一种修正不相容规则的算法。即从相对错误分类率概念出发,在力求保持原知识分类能力的前提下,通过比较不相容规则的相对错误分类率大小,从而对不相容规则进行修正的算法。并通过雷达分类实例验证了算法的可行性。     

简述中水过滤非织造布的性能和应用

分析了在城市污水处理的过滤环节中起相似作用的机织布和非织造布两种过滤材料的各自特点,通过比较指出了机织过滤材料的几点不足。根据非织造布在污水过滤中显示的优良特性,探讨了由不同加工方法生产的新型非织造过滤材料的特点和用途。