Low-energy J/psi-Hadron Interactions from Quenched Lattice QCD

The J/psi-hadron interaction is a key ingredient in analyzing the J/psi suppression in hot hadronic matter as well as the propagation of J/psi in nuclei. As a first step to clarify the J/psi-hadron interactions at low energies, we have calculated J/psi-pi, J/psi-rho and J/psi-nucleon scattering lengths by the quenched lattice QCD simulations with Wilson fermions for beta=6.2 on 24^3*48 and 32^3*48 lattices. Using the Luscher's method to extract the scattering length from the simulations in a finite box, we find an attractive interaction in the S-wave channel for all three systems: Among others, the J/psi-nucleon interaction is most attractive. Possibility of the J/psi-nucleon bound state is also discussed.Comment: 6 pages, 6 figures, talk presented at Lattice 2005 (Heavy quark physics), Trinity College, Dublin, Ireland, 25-30 July 200

An optimization method for designing high rate and high performance SCTCM systems with in-line interleavers

We present a method for designing high-rate, high-performance SCTCM systems with in-line interleavers. Using in-line EXIT charts and ML performance analysis, we develop criteria for choosing constituent codes and optimization methods for selecting the best ones. To illustrate our methods, we show that an optimized SCTCM system with an in-line interleaver for rate r = 5/6 and 64QAM has better performance than other turbo-like TCMs with the same parameters

On the Formation of Coal

The previous theories of the formation of coal have never explained satisfactorily that there are two different kinds of bituminous coal, namely one has the caking property and the other not; however, from the above described observations, the following conclusions may be obtained, because it seems that there is the possibility of the formation of the caking component only when cellulose is in the original materials. Namely, caking coal should have been formed under such conditions, that there were still comparatively large amounts of the decomposition products of cellulose during the huminification processes and the degree of coalification was suitable; on the other hand, when cellulose was decomposed and diminished severely beyond a cirtain degree, sintering or non-caking coal should have been formed. In another words, Fischer's lignin theory may be able to explain only the extreme, or rather exceptional case of the coal formation, and as the general view of this subject the cellulose theory, that not only lignin but also cellulose are the important original material of natural coal, seems in any case to be reasonable

Nitrogen and Sulphur in Coal

As it was considered that the origin of nitrogen in coal was protein, cellulose and lignin were coalified with protein (egg albumin) in water medium at 300°C under corresponding pressure. The behaviors of nitrogen in the artificial coalification processes were observed and the properties of thus obtained coals were examined. Nitrogen in protein is chemically combined with cellulose and lignin, and the proper amount of protein accelerates the huminification of cellulose and the bituminization of lignin. When these nitrogen containing artificial coals are oxidized with alkaline KMnO₄, nitrogen is recovered as NH₃ and NO´₃ almost quantitatively, as same as in the case of natural coals. With this fact, it seems probable that nitrogen in artificial coal is in the same condition of that in natural coal. Cellulose and lignin were artificially coalified in aqueous solutions or suspension of sulfides or sulfates to discuss the origin of sulphur in coal. Water soluble sulfides supply sulphur into artificial coal as organic sulphur, but water insoluble sulfides or sulfates (even water sobluble) do not. It can be concluded that the origin of organic sulphur in coal is water soluble sulfides and that the hypothesis, which explaines that iron sulfates are reduced to pyrite in the coal forming process, seems scarecely probable

Oxygen permeation modelling of perovskites

A point defect model was used to describe the oxygen nonstoichiometry of the perovskites La0.75Sr0.25CrO3, La0.9Sr0.1FeO3, La0.9Sr0.1CoO3 and La0.8Sr0.2MnO3 as a function of the oxygen partial pressure. Form the oxygen vacancy concentration predicte by the point defect model, the ionic conductivity was calculated assuming a vacancy diffusion mechanism. The ionic conductivity was combined with the Wagner model for the oxidation of metals to yield an analytical expression for the oxygen permeation current density as a function of the oxygen partial pressure gradient. A linear boundary condition was used to show the effect of a limiting oxygen exchange rate at the surface