Influence of silver addition on textural properties of new synthetic activated carbon

Starting from macroreticular styrene/divinylbenzene sulfonic acid ion exchange resin the two samples of synthetic activated carbons (SAC), with and without silver, were obtained through carbonization in controlled regime. Detailed sample preparation procedure is described. Characterizations of synthesized samples were conducted using XRD, SEM and N2 physisorption at –196 °C measurements. The influence of applied silver on textural properties of CAS was discussed.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Structural Changes, Dielectric and Ferroelectric Properties of Tribophysically Activated BaTiO3

In order to obtain nanocrystalline material which can be used in MLCC production, the investigations of the influence of BaTiO3 powder tribophysical activation (TPA) on its structural changes, dielectric and ferroelectric properties have been performed. Microstructure development and crystal structure have been studied by mercury porosimetry method, SEM, EDS and X-ray powder diffraction analyses. The modifications of dielectric and ferroelectric properties of sintered samples have been examined and correlated with observed structural changes induced by TPA of starting powders. It has been found that dielectric and ferroelectric properties of tribophysically activated BaTiO3 could be tuned by controlling the grain size and lattice strain of activated nanostructured material

Ionization of hydrogen and hydrogenic ions by antiprotons

Presented here is a description of the ionization of hydrogen and hydrogenic ions by antiproton-impact, based on very large scale numerical solutions of the time-dependent Schr\"odinger equation in three spatial dimensions and on analysis of the topology of the electronic eigenenergy surfaces in the plane of complex internuclear distance. Comparison is made with other theories and very recent measurements.Comment: RevTex document, 11 pages, 4 Postscript figures are available from the authors, in press Phys. Rev. Let

New results on rewrite-based satisfiability procedures

Program analysis and verification require decision procedures to reason on theories of data structures. Many problems can be reduced to the satisfiability of sets of ground literals in theory T. If a sound and complete inference system for first-order logic is guaranteed to terminate on T-satisfiability problems, any theorem-proving strategy with that system and a fair search plan is a T-satisfiability procedure. We prove termination of a rewrite-based first-order engine on the theories of records, integer offsets, integer offsets modulo and lists. We give a modularity theorem stating sufficient conditions for termination on a combinations of theories, given termination on each. The above theories, as well as others, satisfy these conditions. We introduce several sets of benchmarks on these theories and their combinations, including both parametric synthetic benchmarks to test scalability, and real-world problems to test performances on huge sets of literals. We compare the rewrite-based theorem prover E with the validity checkers CVC and CVC Lite. Contrary to the folklore that a general-purpose prover cannot compete with reasoners with built-in theories, the experiments are overall favorable to the theorem prover, showing that not only the rewriting approach is elegant and conceptually simple, but has important practical implications.Comment: To appear in the ACM Transactions on Computational Logic, 49 page

Collective and broken pair states of 65,67Ga

Excited states of 65Ga and 67Ga nuclei were populated through the 12C(58Ni,αp) and 12C(58Ni,3p) reactions, respectively, and investigated by in-beam γ-ray spectroscopic methods. The NORDBALL array equipped with a charged particle ball and 11 neutron detectors was used to detect the evaporated particles and γ rays. The level schemes of 65,67Ga were constructed on the basis of γγ-coincidence relations up to 8.6 and 10 MeV excitation energy, and Iπ=27/2 and 33/2+ spin and parity, respectively. The structure of 65,67Ga nuclei was described in the interacting boson-fermion plus broken pair model, including quasiproton, quasiproton-two-quasineutron, and three-quasiproton fermion configurations in the boson-fermion basis states. Most of the states were assigned to quasiparticle + phonon and three quasiparticle configurations on the basis of their electromagnetic decay properties

Identification and ecology of alternative insect vectors of ‘Candidatus Phytoplasma solani’ to grapevine

Bois noir, a disease of the grapevine yellows complex, is associated with 'Candidatus Phytoplasma solani' and transmitted to grapevines in open fields by the cixiids Hyalesthes obsoletus and Reptalus panzeri. In vine-growing areas where the population density of these vectors is low within the vineyard, the occurrence of bois noir implies the existence of alternative vectors. The aim of this study was to identify alternative vectors through screening of the Auchenorrhyncha community, phytoplasma typing by stamp gene sequence analyses, and transmission trials. During field activities, conducted in Northern Italy in a vineyard where the bois noir incidence was extremely high, nine potential alternative insect vectors were identified according to high abundance in the vineyard agro-ecosystem, high infection rate, and harbouring phytoplasma strains characterized by stamp gene sequence variants found also in symptomatic grapevines. Transmission trials coupled with molecular analyses showed that at least eight species (Aphrodes makarovi, Dicranotropis hamata, Dictyophara europaea, Euscelis incisus, Euscelidius variegatus, Laodelphax striatella, Philaenus spumarius, and Psammotettix alienus/confinis) are alternative vectors of 'Candidatus Phytoplasma solani' to grapevines. These novel findings highlight that bois noir epidemiology in vineyard agro-ecosystems is more complex than previously known, opening up new perspectives in the disease management

Atoms interacting with intense, high-frequency laser pulses: Effect of the magnetic-field component on atomic stabilization

Published versio

Uncertainties in H2 and HD Chemistry and Cooling and their Role in Early Structure Formation

At low temperatures, the main coolant in primordial gas is molecular hydrogen, H2. Recent work has shown that primordial gas that is not collapsing gravitationally but is cooling from an initially ionized state forms hydrogen deuteride, HD, in sufficient amounts to cool the gas to the temperature of the cosmic microwave background. This extra cooling can reduce the characteristic mass for gravitational fragmentation and may cause a shift in the characteristic masses of population III stars. Motivated by the importance of the atomic and molecular data for the cosmological question, we assess several chemical and radiative processes that have hitherto been neglected: the sensitivity of the low temperature H2 cooling rate to the ratio of ortho-H2 to para-H2, the uncertainty in the low temperature cooling rate of H2 excited by collisions with H, the effects of cooling from H2 excited by collisions with H+ and e-, and the large uncertainties in the rates of several of the reactions responsible for determining the H2 fraction in the gas. We show that the most important of the neglected processes is the excitation of H2 by collisions with protons and electrons. This cools the gas more rapidly at early times, and so it forms less H2 and HD at late times. This fact, as well as several of the chemical uncertainties presented here, significantly affects the thermal evolution of the gas. We anticipate that this may lead to clear differences in future detailed 3D studies of first structure formation. Finally, we show that although the thermal evolution of the gas is in principle sensitive to the ortho-para ratio, in practice the standard assumption of a 3:1 ratio produces results that are almost indistinguishable from those produced by a more detailed treatment. (abridged)Comment: 28 pages, 13 figures. Accepted by MNRA

High-spin structure and electromagnetic transition strengths in Cd-104

The recoil distance Doppler shift and Doppler shift attenuation techniques were employed to determine for the first time lifetimes of high spin states in Cd-104in the time range 0.3 ps less than equal to tau less than 1.2 ns. The new experimental results are discussed in the frame of the interacting boson plus broken pair model