m at h . SP ] 1 4 Fe b 19 99 On the Spectrum of the Reduced Wave Operator with Cylindrical Discontinuity

ar X iv : m at h / 99 02 08 6 v 1 [ m at h . SP ] 1 4 Fe b 19 99 THE REDUCED WAVE EQUATION IN LAYERED MATERIALS

Estimation of Sloshing Wave Height in Broad Cylindrical Oil Storage Tanks Using Numerical Methods

Cylindrical steel tanks are important components of many industrial plants such as oil refineries and chemical plants. Usually failure of cylindrical tanks leads to serious consequences. During the past earthquakes such as 1964 Alaska and 1999 Turkey seismic performance of cylindrical tanks revealed that tanks are seismically vulnerable. Therefore, evaluation of seismic performance of these str...

/ 99 02 34 6 v 1 1 5 Fe b 19 99 BS and DS equations in a Wilson loop context in QCD , effective mass operator , qq̄ spectrum

We briefly discuss the quark-antiquark Bethe-Salpeter equation and the quark Dyson-Schwinger equation derived in preceding papers. We also consider the q ¯ q quadratic mass operator M 2 = (w 1 + w 2) 2 + U obtained by three-dimensional reduction of the BS equation and the related approximate center of mass Hamiltonian or linear mass operator H CM ≡ M = w 1 + w 2 + V +. . .. We revue previous re...

ar X iv : m at h / 98 03 12 9 v 1 [ m at h . SP ] 2 6 M ar 1 99 8 SEMI - CLASSICAL STATES FOR NON - SELF - ADJOINT SCHRÖDINGER OPERATORS

We prove that the spectrum of certain non-self-adjoint Schrödinger operators is unstable in the semi-classical limit h → 0. Similar results hold for a fixed operator in the high energy limit. The method involves the construction of approximate semi-classical modes of the operator by the JWKB method for energies far from the spectrum.

On the relations between the point spectrum of A and invertibility of I + f(A)B

Let A be a bounded linear operator on a Banach space X. We investigate the conditions of existing rank-one operator B such that I+f(A)B is invertible for every analytic function f on sigma(A). Also we compare the invariant subspaces of f(A)B and B. This work is motivated by an operator method on the Banach space ell^2 for solving some PDEs which is extended to general operator space under some ...