Study of S-wave ray elastic impedance for identifying lithology and fluid

In this paper, we derive an approximation of the SS-wave reflection coefficient and the expression of S-wave ray elastic impedance （SREI） in terms of the ray parameter. The SREI can be expressed by the S-wave incidence angle or P-wave reflection angle, referred to as SREIS and SREIP, respectively. Our study using elastic models derived from real log measurements shows that SREIP has better capability for lithology and fluid discrimination than SREIS and conventional S-wave elastic impedance （SEI）. We evaluate the SREIP feasibility using 25 groups of samples from Castagna and Smith （1994）. Each sample group is constructed by using shale, brine-sand, and gas-sand. Theoretical evaluation also indicates that SRE1P at large incident angles is more sensitive to fluid than conventional fluid indicators. Real seismic data application also shows that SRE1P at large angles calculated using P-wave and S-wave impedance can efficiently characterize tight gas-sand.

Cosmological constraints on the DGP braneworld model with gamma-ray bursts

We investigate observational constraints on the Dvali, Gabadadze and Porrati （DGP） model with Gamma-ray bursts （GRBs） at high redshift obtained directly from the Union2 Type Ia supernovae data set. With cosmology-independent GRBs, the Union2 set, as well as the cosmic microwave background observation from the WMAP7 result, the baryon acoustic oscillation, the baryon mass fraction in clus- ters and the observed H（z） data, we obtain that the best-fit values of the DGP model are {ΩM0,Ωrc} = {0.235^＋0.015-0.14, 0.138^＋0.o51-0.048}, which favor a flat universe, and the transition redshift of the DGP model is ZT=0.67^＋0.03-0.04.These results lead to more stringent constraints than the previous results for the DGP model.

Estimation of boundary parameters and prediction of transmission loss based upon ray acoustics

Estimation of boundary parameters and prediction of transmission loss using a coherent channel model based upon ray acoustics and sound propagation data collected in field experiments are presented. Comparison between the prediction results and the experiment data indicates that the adopted sound propagation model is valuable, both selection and estimation methods on boundary parameters are reasonable, and the prediction performance of transmission loss is favorable.

The Dimension Paradox in Parameter Space of Cosine Family

It is proved in this paper that the union of escaping parameter rays without endpoints for the cosine family Sκ(z)=eκ(ez+e-z),whereκ∈C is a parameter,has Hausdorff dimension 1,which implies that the ray endpoints alone have Hausdorff dimension 2.This shows that Karpińska’s dimension paradox occurs also in the parameter plane of the cosine family.