Nonlinear ground response at two strong-motion arrays in Taiwan is studied using the spectral ratio technique. At the SMART1 array, we calculate the frequency-dependent soil amplification functions as a ratio of the spectra at alluvium to rock sites, and study their dependence on the excitation level. Horizontal components of shear waves are considered. We… (More)
We show that, when the field strength H of the NS-NS B field does not vanish, the coordinates x and momenta p of open string end points satisfy a set of mixed commutation relations among themselves. Identifying x and p with the coordinates and derivatives of the D-brane world volume, we find a new type of noncommutative space which is very different from… (More)
An ω-language over a finite alphabet X is a set of infinite sequences of letters of X.) is the equality then L is called an I-disjunctive (P-disjunctive, O-disjunctive, respectively) ω-language. Properties concerning such ω-languages are explored and relations between these ω-languages are also studied.
We construct a modification of Churchill and Trotter's trifree objects in e-varieties of locally E-solid semigroups, which have the property, for e-varieties of locally inverse semigroups and for e-varieties of E-solid semigroups, of being isomorphic to the bifree objects.