两性聚氨酯纳米水分散液的制备和性质

制备出了分子链上同时带有酸、碱基团的两性聚氨酯（APU），该两性聚氨酯在酸碱介质中均能形成稳定的纳米水分散液。同时还测定了APU的等电点和水分散液中APU分子链上可离子化基团的含量；实验结果还表明：中和剂浓度对两性聚氨酯纳米水分散液的粒径及稳定性有很大的影响。     

Terahertz planar antennas for future wireless communication: A technical review

With the monotonic increasing demand of the higher bandwidth for the next generation wireless communication system, the extension of the operating frequency of the communication system to the millimeter/Terahertz wave regime of the electromagnetic spectrum where several low-attenuation windows exist is inevitable. However, before the commercial implementation of the wireless communication in these low-attenuation windows, there are various obstacles which need to be addressed by the scientists and researchers. The atmospheric path loss is the main obstacle to the full-fledged implementation of the terahertz wireless communication. The remedy to this problem is the use of high-power sources, efficient detectors and high gain antenna systems. This paper reviews these technical issues with the special attention to the planar antennas which might contribute to the compact, inexpensive, and low profile future terahertz wireless communication system design.     

Faithful compact quantum group actions on connected compact metrizable spaces

We construct faithful actions of quantum permutation groups on connected compact metrizable spaces. This disproves a conjecture of Goswami.     

Solution behavior of a surfactant aldehyde–the oxidation product of an alcohol ethoxylate

It has previously been shown that alcohol ethoxylates readily undergo autoxidation and that one of the major oxidation products is the surfactant aldehyde, i.e. an ethoxylate carrying a –CH₂CHO group at the terminal end of the polyoxyethylene chain. In this work the cloud point, phase behavior and aggregation characteristics of the surfactant aldehyde produced by oxidation of C₁₂H₂₅(OCH₂CH₂)₅OH (C₁₂E₅) are determined and compared with the values obtained with the parent surfactant. It was found that the physico–chemical behavior of the two species was very similar, which indicates that a considerable portion of the aldehyde group is in hydrated state, i.e. the surfactant aldehyde consists of a mixture of aldehyde in carbonyl form and the corresponding geminal diol. The cloud point of the surfactant aldehyde decreased rapidly with time, even when it was stored at low temperature. Also the parent surfactant and its homologue C₁₂E₆ exhibited a decrease in cloud point during storage. For instance, a 1% aqueous solution of C₁₂E₆ showed a cloud point decrease from 62 to 32°C after 4 months storage at 40°C. Such a change in solution behavior can have important practical implications.     

Contractibility and Connectedness of Efficient Point Sets

Using the technique of space theory and set-valued analysis, we establish contractibility results for efficient point sets in a locally convex space and a path connectedness result for a positive proper efficient point set in a reflexive space. We also prove a connectedness result for a positive proper efficient point set in a locally convex space; as an application, we give a connectedness result for an efficient solution set in a locally convex space.     

Plasmonic protection of the hot‐electron energy

In the Letter by K. Kempa, the definitions of two auxiliary constants in Eqs. (10) and (11) were incorrectly given by the author. He now wishes to correct these equations. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Correspondences between the classical electrostatic Thomson problem and atomic electronic structure

Correspondences between the Thomson problem and atomic electron shell-filling patterns are observed as systematic non-uniformities in the distribution of potential energy necessary to change configurations of N ≤ 100 electrons into discrete geometries of neighboring N ? 1 systems. These non-uniformities yield electron energy pairs, intra-subshell pattern similarities with empirical ionization energy, and a salient pattern that coincides with size-normalized empirical ionization energies. Spatial symmetry limitations on discrete charges constrained to a spherical volume are conjectured as underlying physical mechanisms responsible for shell-filling patterns in atomic electronic structure and the Periodic Law.     

Generalization of the Hellmann-Feynman theorem

The well-known Hellmann-Feynman theorem of quantum mechanics connected with the derivative of the eigenvalues with respect to a parameter upon which the Hamiltonian depends, is generalized to include cases in which the domain of definition of the Hamiltonian of the system also depends on that parameter.     

A Stochastic Model for Transport of Particulate Matter in Air: An Asymptotic Analysis

A branching particle system with changes of size is considered as a model for transport of particulate matter in air. This type of model is motivated by problems arising in the context of air pollution. High-density fluctuation limits for the process recording the positions and sizes of the particles through time are presented. These results allow to compute approximate probabilities for the temporal and spatial concentrations of particles of given sizes (in particular the small-sized pollutant particles which pose a health hazard).