Position control and extra-column effects of a microelectrode detector in open-tubular column liquid chromatography

A liquid chromatography system with a potentiometric microelectrode at the exit end of an open-tubular LC column of 3.5m i. d. nearly shows the theoretically [2, 10] predicted performance of 980 000 theoretical plates for non-retained components at a retention time of a few minutes. Possibilities of controlling the position of the microelectrode tip are given. A distance of one column i. d. between detector and column leads to a loss in column performance of about 15%.     

Classical boundary conditions as a technical tool in modern mathematical physics

We review a variety of problems in quantum physics where Dirichlet and Neumann Green's functions enter not as an element in the basic formulation of the problem but as a purely technical tool. Methodology is emphasized.     

On the absorption of eigenvalues by continuous spectrum in regular perturbation problems

We consider the family of operators A + λB with A and B self-adjoint and B relatively form bounded. We consider situations where as λ ↓ λ₁, some eigenvalue μ(λ) approaches the continuous spectrum of A + λB. Typical of our results is the following. If B is relatively form compact, and μ(λ) → μ(λ₁), then either $\text{(μ(λ) ? μ(λ}{}_1\text{))}\text{λ}\text{? λ}{}_1\text{→ 0}\text{or}\text{μ(λ}{}_1\text{)}$ is an eigenvalue of A + λ₁B.     

Scattering theory and quadratic forms: On a theorem of Schechter

We show how to extend Cook's method to a class of pairs whose difference is only a quadratic form.Research supported by U.S. National Science Foundation under Grants MPS-75-11864On leave from Depts. of Mathematics and Physics, Princeton University, Princeton, NY 08540, USA