阻隔型聚对亚苯乙炔电致发光特性研究

报道了一种新的阻隔型聚对亚苯基乙炔的合成与电致发光特性,在聚对亚苯基乙炔主链引入已基碳链,可阻隔聚对亚苯基乙炔的有效共轭长度,改变发光颜色,合成的模型小分子可证明这一点,利用X射线衍射研究了退火前后阻隔型聚对亚苯基乙炔薄膜的晶态变化,研究了电致发光器件ITO/PPE2/Al的电致发光特征。     

Particle surface treatment for nanocomposites containing ceramic particles

Polymer matrix composites containing dispersed ceramic nanoparticles were formed by UV activated photopolymerization from the reactive liquid monomer hexanediol-diacrylate (HDODA). The polymer forming reaction proceeds by a free-radical mechanism. In forming polymer composites that contain nanoparticles, dispersing the particles as discrete entities is critical for developing optimum properties. In the as-received condition, ceramic particles are aggregated. They must be dispersed in the monomer but if the particles are not surface treated and stabilized, they rapidly settle out of the suspension. Surface modification of the ceramic allows the particles to be suspended in the organic monomer and stabilizes the dispersion so that the particles will not reagglomerate. In this study silanes were employed as surface modifiers to disperse two nano-particulate ceramics in the HDODA monomer. The ceramic particles used are silicon carbide (SiC) and barium titanate (BaTiO₃). The shapes and sizes of the ceramic particles were established using transmission electron microscopy (TEM). A method for dispersing nanoparticles was developed in which silane-treated particles were stabilized so that they did not settle out of the liquid monomer. An analytical method based on atomic force microscopy (AFM) was used to characterize the particle distribution in the cured composites. Focusing on work with SiC nanoparticles in HDODA as a model system, the process for silane application was advanced so that it successfully yielded composites having no aggregates with particle sizes closely matching those of the neat ceramic particles.     

The Lu Lu-semigroup for Envelopes Of Functions

In the theory of non-linear smoothers a semigroup of operators has been established, that structures the rank based selectors in a lattice for the purpose of comparison and analysis. The well known upper and lower envelopes of functions can be associated with a pair of operators L and U that allow a similar structure to be defined. The monoid of operators that are compositions of these is established, and the inequalities needed for partially ordering are proved. Some interpretations, analogies and uses are discussed.     

Zinc,chromium and iron silicates as fillers and inorganic colour pigments

Inorganic pigments are characterized by good dispersion and high coating ability. An interesting trend in production of permanent pigment systems may involve a precipitation process followed by roasting of the silica, co-precipitated with metal oxides. The use of zinc silicate may allow elimination of zinc oxide and, partially or even completely, carbon black from rubber mixtures.     

The influence of structure of the interface and interphase on paint adhesion

It has been demonstrated earlier that significant adhesion enhancement to chemically inert polyolefins can be attained through surface grafted connector molecules reactive with oxidized substrate surface. The effectiveness of adhesion improvement through such tethered interfaces was shown to depend on the mode of interaction with the adjacent medium: interpenetration or chemical reaction, as well as surface density and length of grafted molecules. We have frequently observed that some systems, such as in painted products, fail through the delamination of the coating from the substrate surface at the stress levels well below the anticipated load-bearing capacity of the tethered interface. Two interim hypotheses have been formulated to explain the observed phenomenon: (i) The chain scission in surface oxidized polyolefins takes place not only in the uppermost polymer surface, but may propagate into the sub-surface region, thus creating a weak boundary layer which fails cohesively through its bulk, (ii) In order to increase the load-bearing capacity of the interphase, the sub-surface region of the substrate needs to be reinforced by short-chain molecules penetrating into and subsequently providing effective crosslinks between individual fragments of excessively oxidized and hence, weaker sub-surface part of the interphase. In this paper we verify the above hypotheses. The oxidized sub-surface layer reinforced by polyethyleneimine becomes an integral part of the effective interphase in addition to the tethered interface and the interpenetrated network of connector molecules and the paint.     

Can PF2OF exist?

G2 and G3 compound methods were used to explore the possibility that the covalent hypofluorite compound PF₂OF might exist as a stable compound. Calculations suggest that it may exist, making it a legitimate synthetic target. If it is isolable, it is likely to be very reactive, as the O-F bond is expected to be rather weak.     

Right radicals for right distributively generated near-rings

For right near-rings the left representation has always been considered the natural one. However, Hanna Neumann [6] constructed her right near-rings by writing the reduced free group on the left of the near-ring. In [2] and [8] Neumann's ideas are placed in a more general setting in the sense that right R-groups are used to define radical-like objects in the near-ring R. The right 0-radical ^r J ₀(R) and the right half radical ^r J _½(R) are introduced in [2] where it is shown that for distributively generated (d.g.) near-rings R with a multiplicative identity and satisfying the descending chain condition for left R-subgroups ^r J ₀(R) = J ₂(R), the 2-radical from left representation. In this article we introduce the right 2-radical, ^r J ₂(R) for d.g. near-rings and discuss some of its properties. In particular, we show that for all finite d.g. near-rings with identity J ₂(R) = ^r J ₂(R).     

Into isomorphisms in tensor products of Banach spaces

We establish quantitative extensions of two Grothendieck's results on into isomorphisms in projective tensor products. Among others, we prove the following. Let Y be a closed subspace of a Banach space Z and let j : Y → Z denote the identity embedding. If Y is complemented in its bidual Y??, then the injection modulus of the natural inclusion Id ? j : Y??Y → Y??Z satisfies 1/λ _loc (Y,Z) ≤ i(Id ? j) ≤ λ(Y,Y??)/λ(Y,Z), where λ(·,·) and λ_loc(·,·) are, respectively, the projection and the local projection constants.     

Correction to the paper "Embedding c 0 in the space of Pettis integrable functions"

A complete argument is given for the proof of Theorem 5 in [F].     

近临界水中芳香醚与酮Claisen-Schmidt缩合反应的研究

对近临界水介质中不同芳香醛化合物与酮类进行Claisen-Schmidt缩合反应的 研究表明，在没有外加任何催化剂的条件下，芳香醛与酮类可以顺利发生缩合反应 得到α，β－不饱和酮，近临界水在其中兼作溶剂和催化剂。该方法避免了酸或碱 催化剂的使用及随后繁杂的中和、分离步骤，克服了产生废弃盐等弊端。通过对苯 甲醛与苯乙酮在不同条件下的反应研究表明，温度，反应时间和初始水量对反应底 物的转化率和不饱和酮的产率有较大的影响。