Effect of moisture and filler content on the structural,thermal and dielectric properties of polyamide‐6/boehmite alumina nanocomposites

Polyamide‐6 (PA‐6)/boehmite alumina (BA) nanocomposites were prepared via direct melt compounding. Structural, thermal and dielectric properties of ‘as‐received’ (including moisture) and ‘dried’ (thermally treated) specimens were examined. The BA nanofiller was homogeneously dispersed in the PA‐6 matrix. XRD and FTIR revealed that crystallization of PA‐6 in the γ phase was favoured over α phase with increasing BA content. The crystallinity index (CI) and the percentage of α and γ phases were also evaluated. Dried specimens exhibited a lower CI than as‐received specimens while the CI decreased with the addition of filler. Broadband dielectric spectroscopy revealed the presence of γ, β and α relaxations, the Maxwell–Wagner–Sillars effect and the contribution of conductivity relaxation in the as‐received samples. The drying procedure unmasked a double feature of both β and α modes. The results of the complementary techniques were analysed and the effects of moisture and/or the incorporation of BA nanofiller on the microstructure of the PA‐6 matrix are disclosed. © 2019 Society of Chemical Industry     

Isolation,purification, and characterization of the globulin from wheat germ

This research optimized the extraction and purification of globulin from wheat germ and assessed the molecular weight distribution and structure properties of the globulin obtained. The results showed that the relative extraction efficiency and purity of wheat germ globulin (WGG) reached 18.0% and 89.1% under the enzymolysis conditions of 0.32‰ α-amylase, pH 6.5, and 55 °C. The maximal precipitation rate of WGG (91.3%) was obtained with pH 4.3 (acid precipitation). Additionally, the molecular weight of WGG was mainly distributed below 70 kDa. FT-IR confirmed that random coils (30.95%), β-sheet (27.02%), α-helix (26.55%), and β-turn (15.48%) were the secondary structures of WGG. Furthermore, LTQ mass spectrometry showed that WGG was rich in variety and high in complexity, which retrieved 1274 proteins belonging to 392 proteomes by inverse peptide analysis. The findings endow a great potential of preparing WGG with superior functionality for food applications.     

Comparison of fuzzy logic based models for the multi-response surface problems with replicated response measures

A replicated multi-response experiment is a process that includes more than one responses with replications. One of the main objectives in these experiments is to estimate the unknown relationship between responses and input variables simultaneously. In general, classical regression analysis is used for modeling of the responses. However, in most practical problems, the assumptions for regression analysis cannot be satisfied. In this case, alternative modeling methods such as fuzzy logic based modeling approaches can be used. In this study, fuzzy least squares regression (FLSR) and fuzzy clustering based modeling methods, which are switching fuzzy C-regression (SFCR) and Takagi–Sugeno (TS) fuzzy model, are preferred. The novelty of the study is presenting the applicability of SFCR to the multi-response experiment data set with replicated response measures. Three real data set examples are given for application purposes. In order to compare the prediction performance of modeling approaches, root mean square error (RMSE) criteria is used. It is seen from the results that the SFCR gives the better prediction performance among the other fuzzy modeling approaches for the replicated multi-response experimental data sets.     

浅析有效交互技术基础上的网络远程教学

本文主要简单的介绍了网络远程教学的内容,对有效交互技术的相关内容和特点进行了分析,研究将有效交互技术引入网络远程教学中的重要性,探讨网络远程教学中交互技术应用和设计的原则,以思考在交互技术上实施网络远程教学活动的有效措施,从而保障网络远程教学质量。据此,有利于培养学生对网络远程学习的兴趣,充分发挥交互技术的作用,以提高学生的学习效果,实现网络远程教学效益最大化。     

浅谈复杂地质条件下顶管工程施工措施

本文结合琅岐环岛路污水顶管工程,就复杂地质条件下顶管工程采取的施工措施作简要的介绍。     

Distinguishability of interval type-2 fuzzy sets data by analyzing upper and lower membership functions

In this paper, we deal with the problem of classification of interval type-2 fuzzy sets through evaluating their distinguishability. To this end, we exploit a general matching algorithm to compute their similarity measure. The algorithm is based on the aggregation of two core similarity measures applied independently on the upper and lower membership functions of the given pair of interval type-2 fuzzy sets that are to be compared. Based on the proposed matching procedure, we develop an experimental methodology for evaluating the distinguishability of collections of interval type-2 fuzzy sets. Experimental results on evaluating the proposed methodology are carried out in the context of classification by considering interval type-2 fuzzy sets as patterns of suitable classification problem instances. We show that considering only the upper and lower membership functions of interval type-2 fuzzy sets is sufficient to (i) accurately discriminate between them and (ii) judge and quantify their distinguishability.     

钨掺杂M型二氧化钒粉体的水解法制备与结构分析

采用水解法制备不同W掺杂量的VO2(M)粉体。借助于X射线衍射仪、Fourier变换红外谱、差示扫描量热仪、X射线光电子谱仪和X射线精细结构谱对粉体的成分和结构进行表征。结果表明,W6+进入VO2晶格,形成固溶体V4+1-3xV3+2xWxO2。W掺杂降低了VO2(M)的相变温度,相变温度与W掺杂量在一定范围内成线性关系,掺杂效率约为18℃/1%(摩尔分数)。掺杂的大半径W原子部分替换了VO2(M)晶格中的V原子,晶格膨胀畸变产生的压应力通过共享顶点O,沿着W—O—V链传递到邻近的次晶格,造成V—O键键长变化,促使V周围的氧分布对称性随W掺杂量的增加而增大。当W掺杂量增大至2.5%时,单斜结构中的V—O1键和V—V1a键伸长,V—O2键和V—V1b键缩短,V—O1和V—O2峰合并成金红石结构的V—O峰,V—V1a峰和V—V1b峰合并成金红石结构的V—V1峰,即样品已转变为金红石结构。     

苯乙烯精馏阻聚剂性能分析及阻聚措施

苯乙烯是一种重要的有机化工原料,也是最基本的芳烃化学品。苯乙烯在生产过程中极易发生聚合,增加了装置的物耗损失,影响装置的安全稳定生产。本文对乙苯脱氢制苯乙烯、碳八抽提苯乙烯两种苯乙烯生产工艺进行了简单介绍,对苯乙烯自由基聚合以及自引发聚合两种聚合反应机理进行研究,对2,4-二硝基苯酚、2,6-二硝基-对甲苯酚、4,6-二硝基-2-仲丁基苯酚、真阻聚剂4种苯乙烯阻聚剂的物化性质、毒性、使用效果进行比较,提出了真阻聚剂与2,4-二硝基苯酚以及真阻聚剂与4,6-二硝基2-仲丁基苯酚的协同阻聚方案,并提出了降低苯乙烯在工艺系统中的停留时间、维持工艺操作温度稳定、减少系统漏氧量、随系统苯乙烯浓度变化及时调节阻聚剂用量等有效的阻聚措施,从而降低聚合物生成,减少阻聚剂消耗,降低装置物耗,增加装置的经济效益。     

建筑结构胶粘剂的发展和展望

建筑结构胶粘剂经过30多年的发展已成为重要的结构粘接材料。本文综述了建筑结构胶粘剂发展与技术进步。并针对研发、原材料、生产及标准中存在的问题,探讨了其发展方向。