阴离子型聚丙烯酰胺与阳离子表面活性剂的相互作用

采用自由基水溶液共聚法制备了带有负电荷的水溶性聚丙烯酰胺,研究了水溶液中聚合物与阳离子表面活性剂的相互作用及所导致的水溶性、黏度和流变学性质的变化,为进一步研究驱油提供了理论基础.     

A general model of parameterized OWA aggregation with given orness level

The paper proposes a general optimization model with separable strictly convex objective function to obtain the consistent OWA (ordered weighted averaging) operator family. The consistency means that the aggregation value of the operator monotonically changes with the given orness level. Some properties of the problem are discussed with its analytical solution. The model includes the two most commonly used maximum entropy OWA operator and minimum variance OWA operator determination methods as its special cases. The solution equivalence to the general minimax problem is proved. Then, with the conclusion that the RIM (regular increasing monotone quantifier) can be seen as the continuous case of OWA operator with infinite dimension, the paper further proposes a general RIM quantifier determination model, and analytically solves it with the optimal control technique. Some properties of the optimal solution and the solution equivalence to the minimax problem for RIM quantifier are also proved. Comparing with that of the OWA operator problem, the RIM quantifier solutions are usually more simple, intuitive, dimension free and can be connected to the linguistic terms in natural language. With the solutions of these general problems, we not only can use the OWA operator or RIM quantifier to obtain aggregation value that monotonically changes with the orness level for any aggregated set, but also can obtain the parameterized OWA or RIM quantifier families in some specific function forms, which can incorporate the background knowledge or the required characteristic of the aggregation problems.     

Tribological properties of self-assembled monolayers of catecholic imidazolium and the spin-coated films of ionic liquids

A novel compound of an imidazolium type of ionic liquid (IL) containing a biomimetic catecholic functional group normally seen in mussel adhesive proteins was synthesized. The IL can be immobilized on a silicon surface and a variety of other engineering material surfaces via the catecholic anchor, allowing the tribological protection of these substrates for engineering applications. The surface wetting and adhesive properties and the tribological property of the synthesized self-assembled monolayers (SAMs) are successfully modulated by altering the counteranions. The chemical composition and wettability of the IL SAMs were characterized by means of X-ray photoelectron spectroscopy (XPS) and contact angle (CA) measurements. The adhesive and friction forces were measured with an atomic force microscope (AFM) on the nanometer scale. IL composite films were prepared by spin coating thin IL films on top of the SAMs. The macrotribological properties of these IL composite films were investigated with a pin-on-disk tribometer. The results indicate that the presence of IL SAMs on a surface can improve the wettability of spin-coated ionic liquids and thus the film quality and the tribological properties. These films registered a reduced friction coefficient and a significantly enhanced durability and load-carrying capacity. The tribological properties of the composite films are better than those of pure IL films because the presence of the monolayers improves the adhesion and compatibility of spin-coated IL films with substrates.     

Core-shell type multiarm star poly(ε-caprolactone) with high molecular weight hyperbranched polyethylenimine as core: Synthesis, characterization and encapsulation properties

Core-shell type multiarm star copolymers with poly(ε-caprolactone) (PCL) as shells and hyperbranched polyethylenimine (PEI) as core have been successfully prepared by the Sn(Oct)₂ catalyzed ring-opening polymerization of ε-caprolactone (CL) using high molecular weigh PEIs directly as macroinitiators. The initiation efficiency is in the range of 91-95% for PEI with M_n = 10⁴ (PEI10K) and only around 60% for PEI with M_n = 2.5 × 10⁴ (PEI25K), leading to star polymers with an average arm number in the range of 155-276. The thermal property of the obtained multiarm star polymers were also investigated by DSC. The melting and crystallization temperatures of the star polymers increase as the PCL arm length increases when the PEI core is fixed. The fusion enthalpy, crystalline enthalpy and degree of crystallinity values of the star polymers with PEI10K core are less than those with PEI1.8K core. Due to the polarity difference between PCL arm and PEI core, the resulting multiarm star polymers can act as inverted micellar nanocapsules capable of extracting and encapsulating water soluble guests. Increasing the size and polarity of the hydrophilic PEI core of the star nanocapsules are two effective ways to enhance their hydrophilic guest encapsulation capacity. Increasing the hydrophobic PCL arm length can increase the molar ratio, whereas reduce the weight ratio of the encapsulated hydrophilic guests to the star nanocapsules. Unexpectedly, the obtained nanocapsules can entrap the bigger size hydrophilic congo red guests more than the smaller size methyl orange.     

光突发交换边缘路由器性能分析

本文详细分析了各种因素对光突发交换边缘路由器的性能的影响.结果显示,不同服务等级的时延要求可以通过控制组装的最大时延得以保证;不同等级数据包长的大范围变动会导致信道分配的不公平性;边缘节点越多,丢包率越高;在总输出容量一定的情况下,增加输出数据信道数可以在获得低的丢包率的同时达到较高的通道利用率,但随着边缘节点数的增加,增加输出信道数对丢包率的改善作用下降.     

三羟甲基苯酚与部分水解聚丙烯酰胺成胶机理研究

采用13C固体核磁共振技术、X-射线电子能谱及红外光谱技术对部分水解聚丙烯酰胺(HPAM)与三羟甲基苯酚交联前后的结构进行了表征,发现体系中生成仲胺基团的同时伯胺基团有所减少;进一步采用两种表征手段对一系列交联样品进行了测试,定量地计算了仲胺基团含量的增加和伯胺基团含量的减少,得到一致的结果;在此基础上提出了水溶性酚醛交联剂与HPAM的交联机理.     

The orness measures for two compound quasi-arithmetic mean aggregation operators

The paper first summarizes the orness measures and their common characteristics of some averaging operators: the quasi-arithmetic mean, the ordered weighted averaging (OWA) operator, the regular increasing monotone (RIM) quantifier and the weighted function average operator, respectively. Then it focuses on the aggregation properties and operator determination methods for two kinds of quasi-arithmetic mean-based compound aggregation operators: the quasi-OWA (ordered weighted averaging) operator and the Bajraktarevi? mean. The former is the combination of the quasi-arithmetic mean and the OWA operator, while the latter is the combination of the quasi-arithmetic mean and the weighted function average operator. Two quasi-OWA operator forms are given, where the OWA operator is assigned directly or generated from a RIM (regular increasing monotone) quantifier indirectly. The orness indexes to reflect the or-like level of the quasi-OWA operator and Bajraktarevi? mean are proposed. With generating function techniques, the properties of the quasi-OWA operator and Bajraktarevi? mean are discussed to show the rationality of these orness definitions. Based on these properties, two families of parameterized quasi-OWA operator and Bajraktarevi? mean with exponential and power function generators are proposed and compared. It shows that the method of this paper can also be applied to other function-based aggregation operators.     

Dilational Rheological Properties of P-(n-alkyl)-benzyl Polyoxyethylene Ether Carboxybetaine at Water–Decane Interface

The dilational rheological behaviors of absorbed films of p-(n-alkyl)-benzyl polyoxyethylene ether carboxybetaine C_xBE₂CB (x = 8, 10, 12) at the water–decane interface have been investigated by the drop-shape analysis method. The influences of time, oscillation frequency, and bulk concentration on dilational modulus and phase angle have been expounded. The experimental results show that the phase angle of C_xBE₂CB (x = 10, 12) decreases with the increase of time, the slope of the log ? ? log ω curve and phase angle of C_xBE₂CB (x = 10, 12) decrease in a wide concentration range. These phenomena become more and more apparent with the increase of hydrocarbon chain length and it cannot be attributed to the diffusion-exchange process between the bulk and the interface. It is reasonable to consider that ethylene oxide groups are flexible and can be compressed and expanded, just like a spring. Therefore, the compression and expansion of the ethylene oxide groups in the interfacial layer and the exchange between interface and sublayer play a more important role for C_xBE₂CB (x = 10, 12) adsorption film. The dependence of dilational modulus on interfacial pressure can support our provided mechanism strongly.     

An interval type-2 fuzzy sets-based TODIM method and its application to green supplier selection

With the increasing awareness and significant environmental pressures from various stakeholders, companies have realized the significance of selecting green suppliers to their supply chain activities, which involves multiple criteria with uncertainty and the decision makers’ behaviour with irrational. Interval type-2 fuzzy sets (IT2 FSs) have advantages in modelling uncertainty over type-1 fuzzy sets. And TODIM is an useful non-linear prospect model for selecting the irrationally determined alternatives, but the ratings and weights are crisp values. In this paper, we develop the IT2 FSs-based TODIM method to select green supplier. First, we introduce a new distance computing method for IT2 FSs to assist the dominance models to deal with gains (losses) computation. Second, we identify the gains (losses) computing expression through comparing the ranking values of the IT2 FSs evaluations, and obtain the dominance degree of one alternative over others. Third, we use the presented IT2 FSs ranking method using possibility mean and variation coefficient concepts to defuzzify the dominance degree, and obtain the crisp global performance to select the best alternative. Finally, we also apply the proposed IT2 FSs-based TODIM method to green supplier selection for automobile manufacturers.     

Comparative study on enhanced pectinase and alkali-oxygen degummings of sisal fibers

This paper reports an improved traditional fiber degumming method, where sisal fibers were treated by alkali oxygen and pectinase, respectively, after the solute alkali pretreatment. To explore the influence of various factors on its degumming, efficiency of degumming through single factor and orthogonal experiments was aasessed. The results showed that pectinase/alkali-oxygen method after the first alkali treatment had a good effect on the degumming of sisal fiber, and most of the non-cellulose components such as hemicellulose, lignin and pectin had been removed. After pectinase treatment, the cellulose content and crystallinity were 71.87% and 66.29%, respectively. After alkaline oxygen treatment, the cellulose content was 77.16%, and the crystallinity was 69.09%. In terms of degumming rate, alkali oxygen treatment worked better than pectinase treatment, the degumming rate of pectinase method was about 10%, while that of alkali-oxygen method was more than 20%. In other hand, the pectinase method was much milder and had less damage to fibers. It would provide some references for the future application and development of sisal fiber.