含芴共轭高分子的合成、表征及性能研究——推荐一个高分子化学综合实验

推荐了一个高分子化学综合实验——含芴共轭高分子的合成、表征及性能研究。实验内容包括利用Sonogashira偶联反应合成共轭高分子,采用核磁共振和红外光谱等检测手段对其结构进行表征,并利用紫外-可见光谱、荧光和热重分析对其性能进行研究。本实验结合了高分子化学和聚合物仪器分析与表征的知识点,建议纳入高分子专业高年级综合实验课程。     

Applications of Modular Microfluidics Technology

Microfluidics has been widely used in the life science, analytical chemistry, environmental science and other fields in the recent years. Traditional microfluidics systems usually use a highly integrated system with multiple components for handling the fluid in the micro/nano scale. The design and fabrication of integrated microfluidics usually require highly sophisticated instruments and operation professionals. With the experience inherited from integrated circuit and micro electro mechanical system, the modular microfluidics system has been experienced a rapid development in recent years. Modular microfluidics system is a combination of a series of individual modules to achieve complicated liquid handling functions. Compared with conventional microfluidics approach, the modular microfluidics method has the potential in significantly reducing the fabrication cost by using the massive production of single chip, besides, it is easy to be operated, and the user can easily assembly the modules to obtain their customized microfluidics system. The concept of modular microfluidics also indicates the future development path for the standardization of microfluidics system and also provides a promising approach for the industrial massive production of microfluidics. However, the study of modular microfluidics is still in an early stage. Although lots of studies have been conducted with varies materials, fabrication methods and interface technologies, issues like modular interface still restricted the further development of microfluidics. In this paper, a comprehensive review for the latest research on the modular microfluidics and applications in biological and medical fields is provided, and the future research trends of modular microfluidics is also discussed.     

Dispersion of polymeric-coated–silica aerogel particles in unsaturated polyester composites: Effects on thermal-mechanical properties

The thermal-mechanical properties of unsaturated polyester (UP) composite were enhanced by the dispersion of silica aerogel (SA) with preserved pores. Low-cost SA was prepared from rice husk via the sol-gel process and ambient pressure drying. A new method was proposed to encapsulate the hydrophobic aerogel surface pores with hydrophilic polyvinyl alcohol (PVA) film using the fluidized-bed coating process. The dispersion of PVA-coated aerogel with preserved pores in the polyester matrix resulted in an increase of specific compressive strength (44.1?MPa?·?cm³?g^?1), thermal insulation (0.23?W?m^?1?K^?1), and thermal stability (T_onset?=?310°C), but decreased the glass transition temperature (T_g?=?260°C).     

Superlinearly Convergent Infeasible-Interior-Point Algorithm for Degenerate LCP

A large-step infeasible path-following method is proposed for solving general linear complementarity problems with sufficient matrices. If the problem has a solution, the algorithm is superlinearly convergent from any positive starting points, even for degenerate problems. The algorithm generates points in a large neighborhood of the central path. Each iteration requires only one matrix factorization and at most three (asymptotically only two) backsolves. It has been recently proved that any sufficient matrix is a P _*()-matrix for some 0. The computational complexity of the algorithm depends on as well as on a feasibility measure of the starting point. If the starting point is feasible or close to being feasible, then the iteration complexity is . Otherwise, for arbitrary positive and large enough starting points, the iteration complexity is O((1 + )² nL). We note that, while computational complexity depends on , the algorithm itself does not.     

A catalog of minimally nonideal matrices

This paper describes a backtracking algorithm for the enumeration of nonisomorphic minimally nonideal (n ×n) matrices that are not degenerate projective planes. The application of this algorithm forn 12 yielded 20 such matrices, adding 5 matrices to the 15 previously known. For greater dimensions,n = 14 andn = 17, 13 new matrices are given. For nonsquare matrices, 38 new minimally nonindeal matrices are described.Research supported by FNRS grant. Switzerland, while visiting Carnegie Mellon University, Pittsburgh, PA 15213.     

Lattice models of hydrogen-bonded solvents. II

We consider a lattice model of a binary mixture in which each molecule of one component can form zero, one, or two bonds to molecules of the same species on neighboring vertices of the square lattice. We allow the energy of molecules with two bonds to depend on the valence angle, thus generalizing the first paper in this series. If straight polymeric configurations are favored over all others, then a phase transition occurs for low enough temperature. On the other hand, if bent configurations are favored, there is no phase transition. Analogous results are obtained for the hexagonal lattice, where we distinguish energetically betweencis andtrans isomerism of four bonded molecules.Supported by the Danish Science Foundation under grant 511-3635.     

Multicriteria analysis in decision making under information uncertainty

This paper presents results of research related to multicriteria decision making under information uncertainty. The Bellman–Zadeh approach to decision making in a fuzzy environment is utilized for analyzing multicriteria optimization models (X,M models) under deterministic information. Its application conforms to the principle of guaranteed result and provides constructive lines in obtaining harmonious solutions on the basis of analyzing associated maxmin problems. This circumstance permits one to generalize the classic approach to considering the uncertainty of quantitative information (based on constructing and analyzing payoff matrices reflecting effects which can be obtained for different combinations of solution alternatives and the so-called states of nature) in monocriteria decision making to multicriteria problems. Considering that the uncertainty of information can produce considerable decision uncertainty regions, the resolving capacity of this generalization does not always permit one to obtain unique solutions. Taking this into account, a proposed general scheme of multicriteria decision making under information uncertainty also includes the construction and analysis of the so-called X,R models (which contain fuzzy preference relations as criteria of optimality) as a means for the subsequent contraction of the decision uncertainty regions. The paper results are of a universal character and are illustrated by a simple example.     

Stability studies of an electrochemically formed [C60]fullerene-palladium two-component film

The stability of C₆₀ and palladium two-component films, C₆₀/Pd, has been investigated. The effect of different polymerization conditions on the electrochemical stability of the film upon prolonged potential cycling has been studied. Stable voltammetric behavior was observed for polymers formed at potentials less negative than the potential of third C₆₀ reduction step. The incorporation of palladium particles into the structure of C₆₀/Pd polymers increases the polymer stability. The C₆₀/Pd films are doped with supporting electrolyte cations during reduction. The size of these cations is a crucial factor in determining the stability of the film. A strong solvent effect on the potential stability of the film was also observed. The wildest range of stable voltammetric properties was found for acetonitrile and N,N-dimethylformamide. No effect of the temperature on the film stability was observed. The results reported in this work allow for the determination of the optimal conditions for the formation of stable C₆₀/Pd films.     

Enhanced electrochemical performance of submicron LiCoO<Subscript>2</Subscript> synthesized by polymer pyrolysis method

Submicron LiCoO₂ was synthesized by a polymer pyrolysis method using LiOH and Co(NO₃)₂ as the precursor compounds. Experimental results demonstrated that the powders calcined at 800 °C for 12 h appear as well-crystallized, uniform submicron particles with diameter of about 200 nm. As a result, the as-prepared LiCoO₂ electrode displayed excellent electrochemical properties, with an initial discharge capacity of 145.5 mAh/g and capacity retention of 86.1% after 50 cycles when cycled at 50 mA/g between 3.5 and 4.25 V. When cycled between 3.5 and 4.5 V, the discharge capacity increased to 177.9 mAh/g with capacity retention of 85.6% after 50 cycles.     

Browder spectra for upper triangular operator matrices

When A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimensional separable Hilbert space H⊕K of the form . In this paper, we prove that