Synthesis,crystal structure and optical properties of quasi-one-dimensional lead (II) iodide: C14H18N2Pb2I6

Quasi-one-dimensional lead (II) iodide compound, C₁₄H₁₈N₂Pb₂I₆, with unique crystal structure was synthesized and solved for the crystal structure. These novel inorganic-organic hybrids have high thermal stability of upto 300 °C and show excitonic and charge-transfer features in their optical properties. An attempt has been made to understand the structural and optical mechanisms between inorganic one-dimensional polymeric PbI nano ribbons and the guest organic moiety for future applications in nanoscaled electronic devices.     

The existence of weakly symmetric and weakly Ricci-symmetric Sasakian manifolds admitting a quarter-symmetric metric connection

The object of the present work is to obtain a necessary condition for the existence of weakly symmetric and weakly Ricci-symmetric Sasakian manifolds admitting a quarter-symmetric metric connection.     

Highly facile and stereoselective intramolecular [2 +2]photocycloadditions of bis(alkenoyl)ketenedithioacetals

The conformational change induced by the introduction of a ketenedithioacetal moiety at C-4 of 1,7-substituted-1,6-heptadiene-3,5-diones results in favorable spatial relationships between the alkenoyl groups to effect efficient intramolecular cycloadditions: irradiation of bis(alkenoyl)ketenedithioacetals in solution leads to facile and stereospecific intramolecular [2 + 2] photocycloadditions resulting in the formation of substituted bicyclo[3.2.0]heptane-2,4-diones, the observed conformational rigidity of which is attributed to the push-pull character of the ketenedithioacetal group.     

Stretching and collapse of neutral polymer layers under association with ionic surfactants

We provide experimental evidence for stretching and collapse of neutral polymer layers, already adsorbed at an oil-in-water interface, due to its interaction with surfactants. Upon stretching, the first interaction length (2L(0)) follows a power law dependence on surfactant concentration ( proportional, variant C(x)(s), where x approximately 0.5 for cationic surfactants) and collapses in the presence of salt, as a relatively weak power law (C(-y)(s), where y=0.17), in good agreement with brush length decay for polyelectrolyte brushes.     

Electronic structure of non-magnetic impurities in dilute alloys of Al

The electronic structure of substitutional non-magnetic impurities Cu, Ag, Cd, Mg, Zn, Ga, In, Ge, Si and Sn in Al is studied using density functional theory. A simple physical model is proposed to calculate the effective charges on impurities in trivalent metal Al. A linear relation is found between the effective charges on impurities and impurity vacancy capture radii. The spherical solid model (SSM) is used to account for discrete nature of the host. The impurity-induced change in charge density, scattering phase shifts, host-impurity potential, residual resistivity and impurity self-energy are calculated. Higher order scattering phase shifts are found significant and the host-impurity potential is found proportional to effective charge on impurity in its vicinity. The self-consistently calculated potential is used to calculate the electric field gradients (EFGs) at the first and second nearest neighbours (1NNs, 2NNs) of impurity. The calculated values are in agreement with the experimental results.     

Target mass dependence of charged particle multiplicity inp-nucleus interactions

The shower particle multiplicity (〈n _s 〉) in thep-nucleus interactions for different targets, in the incident energy range of ～6–500 GeV has been studied. The variation of multiplicity parameters with target mass (A) or with number of interactions that the incident hadron suffers inside the nucleus (v _A ) and with the changed particle multiplicity inp-p interactions (〈n _ch〉) has been examined in the light of the various models of multiparticle production. The present analysis favours the hydrodynamical model though some other models can not be conclusively ruled out.     

Eine Apparatur zur raschen Mikrobestimmung des pH- und pCl-Wertes von L?sungen

Ohne Zusammenfassung     

Steady pulse propagation in an inhomogeneously broadened resonant medium

Steady propagation of a single pulse in an inhomogeneously broadened resonant medium is studied. 2π-pulse solutions which are slightly different from those given in the literature are reported and it is shown that π-pulse solutions do not exist.