Chromatographic behavior of xanthines in aqueous normal phase chromatography using titania stationary phase

The chromatographic behavior of native titania was investigated in aqueous normal phase chromatography using a set of N-methylated xanthines as polar test solutes. In agreement with a hydrophilic interaction on a polar bed, the retention of xanthine models increased mainly along their molecular polarity. Adsorption of these molecules on the hydrated surface of titania prevailed as a retention mechanism for low water contents in the mobile phase. Several N-methylated xanthines could be easily discriminated along the number and position of their methyl groups while the nitrogen atom at position 3 was found deeply involved in the retention on titania. To get further insights on the interactions occurring on the surface of titania, the retention of xanthine derivatives based on ligand-exchange was evaluated as a function of the buffer concentration and type. The separation efficiency of native titania for the set of N-methylated xanthines was comparable to that observed on zirconia but lower than that obtained on native silica due to mixed-mode interactions. However, titania exhibited a superior ability to recognize several isomeric positions of xanthine derivatives in comparison to zirconia and silica.     

山东半岛与长三角、珠三角城市群综合竞争力比较研究

客观地评价山东半岛城市群综合竞争力的现状, 对其可持续发展具有重要的作用. 运用ANP (Analytic Network Process)方法从综合经济实力、居民生活质量、交通运输与通讯、科技创新力4方面构建城市群竞争力评价指标体系, 建立城市群竞争力多指标非线性综合评价决策模型, 对山东半岛与长江三角洲、珠江三角洲城市群进行实证比较研究. 揭示山东半岛城市群在经济增长速度、医疗卫生与环境保护、教育资源等方面具有竞争优势, 但在经济总体实力、科技研发投入与产出比、交通与通讯建设等方面明显滞后.     

A systematic procedure to evaluate an automobile manufacturer–distributor partnership

Automobile manufacturer–distributor partnerships are fundamental to the success of automobile companies. The complexity of the overall partnership model often causes difficulties in partnership study. This paper presents a systematic procedure to evaluate an automobile manufacturer–distributor partnership consisting of a large number of system variables. Firstly, Interpretive Structure Modeling (ISM) is used to sort system variables into groups of various characteristics. This sorting process provides an effective means to develop a three-stage hierarchic/network model of the partnership, including Stage I: partnership selection, Stage II: partnership establishment, and Stage III: partnership maintenance. Secondly, Analytic Hierarchy Process (AHP)/Analytic Network Process (ANP) are applied to partnership evaluation based on as many as 20 system variables. Relative importance weight of all variables is quantitatively determined. The most investment-worthy variables found are management strength and power. Finally, this paper makes a comparison between the optimum distributors identified by the present procedure and in practical cases. The usefulness and efficiency of the proposed procedure are ascertained with highly consistent results in the comparison.     

A novel two-phase group decision making approach for construction project selection in a fuzzy environment

This paper considers a construction project problem under multiple criteria in a fuzzy environment and proposes a new two-phase group decision making (GDM) approach. This approach integrates a modified analytic network process (ANP) and an improved compromise ranking method, known as VIKOR. To take uncertainty and risk into account, a new decision making approach is presented with multiple fuzzy information by a group of experts, and a risk attitude for each expert is incorporated that can be expressed linguistically. First, a modified fuzzy ANP method is introduced to address the problem of dependence as well as feedback among conflicting criteria and to determine their relative importance. Then, a fuzzy VIKOR method is extended to rank potential projects on the basis of their overall performance. An illustrative example from the literature is provided for the construction project problem to demonstrate the effectiveness and feasibility of the proposed approach. The computational results show that the proposed two-phase GDM approach is suitable to cope with imprecision and subjectivity for the complicated decision making problem. Finally, the associated results of the proposed approach with risk attitudes and without risk attitudes are compared with the results reported by Cheng and Li [1], and the merits are highlighted.     

Carbon nuclear magnetic resonance spectroscopic fingerprinting of commercial gasoline: Pattern-recognition analyses for screening quality control purposes

In this work, the combination of carbon nuclear magnetic resonance (¹³C NMR) fingerprinting with pattern-recognition analyses provides an original and alternative approach to screening commercial gasoline quality. Soft Independent Modelling of Class Analogy (SIMCA) was performed on spectroscopic fingerprints to classify representative commercial gasoline samples, which were selected by Hierarchical Cluster Analyses (HCA) over several months in retails services of gas stations, into previously quality-defined classes. Following optimized ¹³C NMR-SIMCA algorithm, sensitivity values were obtained in the training set (99.0%), with leave-one-out cross-validation, and external prediction set (92.0%). Governmental laboratories could employ this method as a rapid screening analysis to discourage adulteration practices.     

基于ANP与模糊TOPSIS-CRITIC方法的不确定多属性决策模型

随着多属性决策问题的日益流行,处理决策问题的复杂程度也逐渐增加,针对其中权重不确定,难以量化各影响因素主观权重与客观权重以及指标排序不精确的问题,提出了一种将网络层次分析法(ANP)与模糊指标相关性的指标权重确定法(CRITIC)、逼近理想解排序法(TOPSIS)相结合的不确定多属性决策模型首先,在分别使用ANP方法和CRITIC法确定各影响因素的主观、客观权重的基础上计算指标的综合权重,然后应用模糊TOPSIS方法对备选方案进行贴进度排序最后,通过一个实例将计算结果同其他三种决策方法进行对比分析,验证了所提出的ANP与模糊TOPSIS-CRITIC方法的可靠性和有效性.     

积合成模型是唯一保序合成模型的条件

在层次分析(AHP)中,积合成模型是保序的,如果想得到只有积合成模型保序的结论,还必须限定属性个数大于2.     

Passivation of the surface of aluminum nanopowders by protective coatings of the different chemical origin

The results of investigation and analysis of electro-exploded aluminum nanopowders, whose surface were passivated with the following substances: liquids - nitrocellulose (NC), oleic acid (C₁₇H₃₃COOH) and stearic acid (C₁₇H₃₅COOH), suspended in kerosene and ethanol, fluoropolymer; solids - boron and nickel; gases - N₂, CO₂ and air (for a comparison) are discussed. The surface protection for the aluminum nanopowders by coatings of different chemical origins leads to the some advantages of the powders properties for an application in energetic systems, e.g. solid propellants and “green” propellants (Al-H₂O). Aluminum nanopowders with a protected surface showed the increased stability to oxidation in air during the storage period and higher reactivity by heating. The TEM-visual diagram of the formation and stabilization of the coatings on the particles has been proposed on the basis of experimental results. The kinetics of the interaction of aluminum nanopowders with air has been discussed. The recommendations concerning an efficiency of the protective “non-Al₂O₃” layers on aluminum nanoparticles were proposed.     

An integrated FANP–MOLP for supplier evaluation and order allocation

In the face of acute global competition, supplier management is rapidly emerging as a crucial issue to any companies striving for business success and sustainable development. To optimize competitive advantages, a company should incorporate “suppliers” as an essential part of its core competencies. Supplier evaluation, the first step in supplier management, is a complex multi-criteria decision-making (MCDM) problem, and its complexity is further aggravated if the highly important interdependence among the selection criteria is taken into consideration. The objective of this paper is to suggest a comprehensive decision method for identifying top suppliers by considering the effects of interdependence among the selection criteria, as well as to achieve optimal allocation of orders among the selected suppliers.     

A simple method to improve the consistency ratio of the pair-wise comparison matrix in ANP

Tests of consistency for the pair-wise comparison matrices have been studied extensively since AHP was introduced by Saaty in 1970s. However, existing methods are either too complicated to be applied in the revising process of the inconsistent comparison matrix or are difficult to preserve most of the original comparison information due to the use of a new pair-wise comparison matrix. Those methods might work for AHP but not for ANP as the comparison matrix of ANP needs to be strictly consistent. To improve the consistency ratio, this paper proposes a simple method, which combines the theorem of matrix multiplication, vectors dot product, and the definition of consistent pair-wise comparison matrix, to identify the inconsistent elements. The correctness of the proposed method is proved mathematically. The experimental studies have also shown that the proposed method is accurate and efficient in decision maker’s revising process to satisfy the consistency requirements of AHP/ANP.