Quantum suppression of the generic chaotic behavior close to cosmological singularities

In classical general relativity, the generic approach to the initial singularity is very complicated as exemplified by the chaos of the Bianchi IX model which displays the generic local evolution close to a singularity. Quantum gravity effects can potentially change the behavior and lead to a simpler initial state. This is verified here in the context of loop quantum gravity, using methods of loop quantum cosmology: The chaotic behavior stops once quantum effects become important. This is consistent with the discrete structure of space predicted by loop quantum gravity.     

The first liquid-crystalline, expanded porphyrins

Aliphatic derivatives of hydrazinophyrin, a new type of tetrapyrrolic macrocycle prepared by the condensation of 2,5-diformylpyrroles with hydrazine, exhibit liquid crystalline properties as judged from polarising optical microscopy; these hydrazinophyrins appear to be the first mesogens derived from an expanded porphyrin core.     

Electronic excitation spectra of doublet anion radicals of cyanobenzene and nitrobenzene derivatives: SAC-CI theoretical studies†

Electronic ground and excited states of anion radicals of cyanobenzene derivatives: 1,3,5-tricyanobenzene, 1,2,4,5-tetracyanobenzene, and tetracyanoquinodimethane (TCNQ) and nitrobenzene derivatives: nitrobenzene, p-nitroaniline, m-nitroaniline, and o-nitroaniline were theoretically investigated by the symmetry adapted cluster-configuration interaction (SAC-CI) method, which is able to produce accurate theoretical electronic excitation spectra even for radical doublet states. For all the target molecules, the present calculations reproduced the positive electron affinities, which were mostly in good agreement with the experimental values, and their features, especially for TCNQ, were characterised by singly occupied molecular orbitals as well as the number of the electron-withdrawing terminal groups. The excitation energies and their oscillator strengths by the SAC-CI method were also in good agreement with the corresponding experimental UV/VIS/NIR spectra observed by one of the authors and other experimental evidences. Except for TCNQ, the present theoretical calculations were successful to first predict the existences of the forbidden (or very low intense) pure valence excited states in near-infrared region. The physical natures of the observed intense spectral bands were clarified and some new assignments to their electronic states were provided. By extending the present work, photo-related molecular designs of new functional electron acceptors may be challenged.     

Piezoelectric relaxations in polymers: Spherical dispersion model

For the interpretation of piezoelectric relaxation in oriented polymers, a spherical dispersion model is proposed in which piezoelectric spheres are dispersed in a nonpiezoelectric medium. The influence of the dielectric and elastic relaxations in the medium and the sphere on the piezoelectric stress constant and strain-constant is analyzed in detail. The origins of piezoelectric relaxations in oriented poly-γ-methyl-L-glutamate are assigned to the elastic relaxation (at about ?70°) and the dielectric relaxation (at about 0°C) in the piezoelectric phase, and the elastic relaxation (at about 100°C) in the non-piezoelectric phase, respectively.     

Controllability and Controller-Observer Design for a Class of Linear Time-Varying Systems

In this paper a class of linear time-varying control systems is considered. The time variation consists of a scalar time-varying coefficient multiplying the state matrix of an otherwise time-invariant system. Under very weak assumptions of this coefficient, we show that the controllability can be assessed by an algebraic rank condition, Kalman canonical decomposition is possible, and we give a method for designing a linear state-feedback controller and Luenberger observer.     

Discotic salicylaldimato metal complexes exhibiting columnar mesophases and their mixtures with rod-like salicylaldimato complexes

The synthesis and mesomorphism of a series of discotic metal complexes of salicylaldimine ligands is reported. None of the ligands was mesomorphic, but the longer chain length complexes showed a Col_h phase as evidenced by optical microscopy. Phase diagrams were constructed using rod- and disk-like salicylaldimato complexes, where one was designed to have Lewis acid characteristics and the other Lewis base properties. It was hoped that an associative Lewis acid/base interaction would prevent phase separation of the two components, which may point a way to the realization of a mixture with a biaxial nematic phase. The form of the phase diagrams is discussed.