漂浮法制备SiO2有序大孔材料

用漂浮组装方法以亚微米尺度单分散的聚苯乙烯(PS)微球作为模板, 在悬浮液气-液界面处组装PS模板微球与纳米级胶体颗粒, 形成二元胶体颗粒共混物, 再去除模板得到有序大孔材料.     

Adsorption and structural properties of channel-like and cage-like organosilicas

Channel-like and cage-like mesoporous silicas, SBA-15 (P6mm symmetry group) and SBA-16 (Im3m symmetry group), were modified by introducing single ureidopropyl surface groups, mixed ureidopropyl and mercaptopropyl surface groups, and single bis(propyl)disulfide bridging groups. These hexagonal and cubic organosilicas were prepared under acidic conditions via co-condensation of tetraethyl orthosilicate (TEOS) and proper organosilanes using poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) amphiphilic block copolymer templates, P123 (EO₂₀PO₇₀EO₂₀) and F127 (EO₁₀₆PO₇₀EO₁₀₆). The modified SBA-15 and SBA-16 materials were synthesized by varying the molar ratio of organosilane to TEOS in the initial synthesis gel. The removal of polymeric templates, P123 and F127, was performed with ethanol/hydrochloric acid solution. In the case of SBA-15 the P123 template was fully extracted, whereas this extraction process was less efficient for the removal of F127 template from the SBA-16-type organosilicas; in the latter case a small residue of F127 was retained. The adsorption and structural properties of the resulting materials were studied by nitrogen adsorption-desorption isotherms at −196^∘C (surface area, pore size distribution, pore volumes), powder X-Ray diffraction, CHNS elemental analysis and high-resolution thermogravimetry. The structural ordering, the BET specific surface area, pore volume and pore size decreased for both channel-like and cage-like mesoporous organosilicas with increasing concentration of incorporated organic groups.     

N-fuzzy Filters in Ordered Semigroups

In this paper we define N-fuzzy filters,N-fuzzy bi-ideal subsets and N-fuzzy bi-filters of ordered semigroups and characterize ordered semigroups in terms of N-fuzzy filters, N-fuzzy bi-ideal subsets and N-fuzzy bi-filters.We establish relationship of N-fuzzy filters and prime N-fuzzy ideals of ordered semigroups. Also we discuss the relationship of N-fuzzy bi-filters and prime N-fuzzy bi-ideal subsets of ordered semigroups.     

Within-season dismissal of football coaches: Statistical analysis of causes and consequences

The paper examines the triggers for, and, consequences of, within-season dismissals of managers (head coaches) in the top division of the Spanish Football League during seasons 2002–2003 to 2004–2005. A major reason for directors deciding on dismissal is shown to have been concern that the club in question was in danger of demotion out of the division. This suggests that the clubs hoped to bring about short-term improvement in performance by changing manager. Employing an ordered probit model of match results, we demonstrate that an improvement in results tended to be achieved but only in home matches. The finding vindicates the decisions taken by club directors who dismissed their managers and implies that appeasing fans can have on-the-field benefits. It is consistent with the importance attributed to crowd support in the literature on home advantage in sports.     

Finding strong defining hyperplanes of Production Possibility Set

Production Possibility Set (PPS) is defined as the set of all inputs and outputs of a system in which inputs can produce outputs. Data Envelopment Analysis models implicitly use PPS to evaluate relative efficiency of Decision Making Units (DMUs). Although DEA models can determine the efficiency of a DMU, they cannot present efficient frontiers of PPS. In this paper, we propose a method for finding all Strong Defining Hyperplanes of PPS (SDHP). They are equations that form efficient surfaces. These equations are useful in Sensitivity and Stability Analysis, the status of Returns to Scale of a DMU, incorporating performance information into the efficient frontier analysis and so on.     

二阶非线性脉冲积分-微分方程初值问题的解

该文利用单调迭代技术讨论了Banach空间中含有非线性一阶微分项x'的二阶脉冲积分-微分方程初值问题的最大最小解的存在性问题. 作为该文主要结论的应用,作者给出了一个例子.     

Bounds for the Local Distance Between Arithmetical Distributions

We obtain upper and lower bounds for the local distance ρ(ν _x ,P _x ). Here ν _x is the distribution of a set of strongly additive functions f _x with respect to the usual frequency on the set of positive integers, and P _x is the distribution of the sum of suitably chosen independent random variables. We consider the case where f _x (p)∈{0,1,2,…,C} for all prime numbers p with some fixed positive integer C.      

覆盖S-粗集模型的性质

讨论基于覆盖理论的S-粗集模型的性质,给出了S-粗集生成的拓扑结构,证明了覆盖S-粗集模型与自反、传递关系下的S-粗集模型是等价的。     

A new approach for modeling and solving set packing problems

In recent years the unconstrained quadratic binary program has emerged as a unified modeling and solution framework for a variety of combinatorial optimization problems. Experience reported in the literature with several problem classes has demonstrated that this unified approach works surprisingly well in terms of solution quality and computational times, often rivaling and sometimes surpassing special purpose methods. In this paper we report on the application of this unified framework to set packing problems with a variety of coefficient distributions. Computational experience is reported illustrating the attractiveness of the approach. In particular, our results highlight both the effectiveness and robustness of our approach across a wide array of test problems.