Chlorination of Calix[4]arene Derivatives

New convenient method for synthesis of p-chlorinated calix[4]arenes is reported. The sulfuryl chloride was used for chlorination of unsubstituted at the lower rim calix[4]arenes. The products of this reaction were very suitable for further O-alkylation.     

Self-Organization and Resource Exchange in EVS Modeling

Two versions of a model, named Resource, were developed within the Ensembles with Variable Structure (EVS) approach. The EVS-approach represents interacting groups (populations) with a flexible structure of connections and a diversity of elements (agents), where agents possess an abstract set of characteristics, and seek to form connections with other agents according to the degree of compatibility between these characteristics. The model presented here studied a role of parameters related to a flow of resource through the agents of a population. Individual sociability appeared to be a key parameter in the self-organization of the population. The percentage of an individual resource that an agent is allowed to spend was also an important resource-related parameter. Some other phenomena are reported as well.     

Manifestations of quasi-one-dimensional correlations in the electronic properties of transition-metal oxides

As follows from the string model, the pseudogap anomalies in the electronic properties of lightly doped cuprates, observed by different methods, can be explained by the segregation of charge carriers into bosonic stripes. The comparative investigation of the similar anomalies revealed in several “copperless” transition-metal oxides reliably suggests that these anomalies are likely to be due to the analogous processes of quasione-dimensional structurization of paired charge carriers into a metastable network of conducting nanochannels.     

Effects of resistance switching in niobium oxides: Metastable nanochannels

The recent experimental data suggest that lattice defects in transition-metal oxides tend to be aligned into chains, which can promote pairing of charge carriers with subsequent formation of bosonic stripes. In this study, possible relationship between the extraordinary manifestations of electronic properties, observed by different methods in niobium oxides, and the processes of formation of metastable nanochannels from bosonic stripes are discussed.     

Discrete nature of superconducting nanochannels in the cuprate pseudogap regime at <Emphasis Type="Italic">T</Emphasis> > 200 K

Intensification of segregation processes with a decrease in the charge carrier concentration in cuprates should lead, according to the string model, to a decrease the discrete width w _ν of dominant bosonic stripes and an increase in their critical temperature T _c up to 1200 K. A comparison of the simulated results with the experimental data gives grounds to conclude that the anomalies of the electronic properties observed in the pseudogap regime of lightly dopes cuprates are most likely to be due to the formation of a metastable network of superconducting nanochannels with T _c > 200 K from the bosonic stripes limited by w _ν ≤ 2 nm.