百叶窗浓缩器气固两相流动的试验研究

本文在以往试验基础上对百叶窗浓缩器进行了更加深入的试验研究，分析了百叶窗结构、气流等因素对浓缩器性能，即浓淡风比、阻力系数、浓缩率三个参数的影响，从而得到了优化的百叶窗结构。     

A Sequence of Diagnosis and Repair for a 2-State Repairable System

This paper presents a desireable sequence of diagnosis and repair for a failed 2-state repairable system regardless of s-coherence, and the calculation method of this sequence. Compared with my earlier sequence, this sequence considers the information known from the diagnosis and repair. An example illustrates the method.     

关于Ekeland—Caristi定理的一点注记

1.引言 为适应讨论映象满射性等问题的需要,W.O.Ray和A.M.Walker在[1]中对Ekeland—Caristi定理作了新的推广,获得如下的结果: 定理1.1 设(M,d)为完备距离空间,:M→[0,∞)下半连续,C:[0,∞)→[0,∞)连续,不增,且integral from 0 to ∞(C(s)ds=∞)。x_0∈M为某一固定点。若映象g:M→M满足     

Linear π‐conjugated polymers containing 2,4,6‐tris(thiophen‐2‐yl)‐1,3,5‐triazine unit: Synthesis and optical properties

Some linear π‐conjugated polymers containing 2,4,6‐tris(thiophen‐2‐yl)‐1,3,5‐triazine unit were synthesized via Sonogashira or Suzuki reaction for the first time and characterized by IR, NMR, and GPC. Because of the introduction of 2,4,6‐tris(thiophen‐2‐yl)‐1,3,5‐triazine unit into π‐conjugated system, all polymers exhibited good thermal stability with high decomposition temperature. Their optical and electrochemical properties were investigated. Based on the 2,4,6‐tris(thiophen‐2‐yl)‐1,3,5‐triazine unit linked with different aromatic rings, the polymers showed the tunable fluorescence from blue to blue‐green emission with satisfied quantum yield. Cyclic voltammetry measurement indicated that the LUMO and HOMO levels of the polymers could be adjustable through the main‐chain structural modification. All polymers had low LUMO level (?2.86 to ?3.06 eV) due to the high‐electron affinity of triazine unit. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 702–712, 2008     

Adaptive decomposition finite difference methods for solving singular problems—A review

Decomposition, or splitting, finite difference methods have been playing an important role in the numerical solution of nonsingular differential equation problems due to their remarkable efficiency, simplicity, and flexibility in computations as compared with their peers. Although the numerical strategy is still in its infancy for solving singular differential equation problems arising from many applications, explorations of the next generation decomposition schemes associated with various kinds of adaptations can be found in many recent publications. The novel approaches have been proven to be highly effective and reliable in operations. In this article, we will focus on some of the latest developments in the area. Key comments and discussion will be devoted to two particularly interesting issues in the research, that is, direct solutions of degenerate singular reaction-diffusion equations and nonlinear sine-Gordon wave equations. Numerical experiments with simulated demonstrations will be given.     

Microwire-based analog of a quarter-wavelength radioabsorber

A periodic structure made of microwires placed above a metal screen is considered. Conditions for matching this structure with free space are obtained. It is shown that given small enough period of the structure and satisfaction of the matching conditions the frequency dependence of reflection coefficient is close to that of a quarter-wavelength layer. The possibility of varying wire impedance and their placement geometry in a wide range provides control of radioabsorber’s frequency figure.     

The influence of interlayer cations on the photo‐oxidative degradation of polyethylene/montmorillonite composites

The photo‐oxidative degradation of polyethylene/montmorillonite (PE/MMT) nanocomposite and microcomposite has been investigated. It has been found that the rate of photo‐oxidative degradation of PE/MMT nanocomposite and PE/Mⁿ⁺MMT (where Mⁿ⁺ stands for multivalent transition metal cation) microcomposites is much faster than that of pure PE. For the PE/MMT nanocomposite, the acceleration of photo‐oxidative degradation is due to the influence of MMT and ammonium ion, in which the influence of ammonium is primary. The decomposition of ammonium ion may create acidic sites on layered silicates; meanwhile, the complex crystallographic structure and habit of clay minerals could also result in some active sites. The reversible photo‐redox reaction of transition metal cations has a catalytic effect in the degradation of the polymer matrix. All these catalytic active sites can accept single electrons from donor molecules of polymer matrix and induce the formation of free radical upon UV irradiation. The generation of free radical leads to the oxidization and break of molecular chain. Thus, the materials suffer degradation and their mechanical strength decreases. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3006–3012, 2004     

Iterative processes for common fixed points of two different families of mappings with applications

In this paper, an implicit iterative process is investigated for common fixed points of two different families of nonlinear mappings. Theorems of strong and weak convergence are established in real Hilbert spaces. As an application of the iterative process, inclusion problems are considered.